Introduction
The importance of discussing the topic of disbelief and its clarification which is found in the following:
1.   The obligation of warning about disbelief and distancing from it, as the servant becomes wretched both in this world and in the hereafter. This is the greatest offence and sin, it is dangerous, it is worse an event and negatively impactful. It is the scariest thing which believers fear and are vigilant about. Allah, the Most High, states, “And whoever denies the faith - his work has become worthless, and he, in the Hereafter, will be among the losers.” Al-Maa’idah:5

As-Sa’dee states, “Who disbelieves in Allah, the Exalted, and on all those things that are compulsory to believe in such as the His Books, Messengers and anything from the Laws of religion, then his deeds have been rendered worthless on condition that he dies on his disbelief, as Allah, the Exalted, states: “And whoever of you reverts from his religion to disbelief and dies while he is a disbeliever - for those, their deeds have become worthless in this world and the Hereafter.” Al-Baqarah: 217 “And he, in the Hereafter, will be among the losers,” means that such people will lose their selves, wealth, and families on the day of Judgement and they will receive eternal wretchedness.” [7] Tayseer al-Kareem ar-rahmaan, p.222. Allah, Almighty and Majestic, states, “And whoever exchanges faith for disbelief has certainly strayed from the soundness of the way.” Al-Baqarah: 108 Ibn Katheer comments, “One who purchases disbelief in lieu of belief, then ‘has certainly strayed from the soundness of the way,’ meaning, that he has left the straight path and has gone to ignorance and deviance … , just as what the Almighty stated:  “Have you not considered those who exchanged the favour of Allah for disbelief and settled their people in the home of ruin? It is Hell, which they will enter to burn, and wretched is the settlement.” Ibraaheem: 28-29 [8] Tafseer al-Qur’an al-‘Adheem, vol.1, p.382.

2.   The outcome of disbelief in the hereafter is an eternal abode for its adherent in the hellfire.  Allah has explicitly mentioned the eternal abode of the disbelievers in the punishment of the fire in three places of His Book:

The first place: In the last part of Surah An-Nisaa’ wherein Allah Almighty and Majestic, states: “Indeed, those who disbelieve and avert people from the way of Allah have certainly gone far astray. Indeed, those who disbelieve and commit wrong or injustice - never will Allah forgive them, nor will He guide them to a path, except the path of Hell; they will abide therein forever. And that, for Allah, is always easy.” An-Nisaa’: 167-169  Ibn Jareer states: In ‘they will abide therein forever,’ Allah is stating that they will stay therein forever. In ‘And that, for Allah, is always easy,’ Allah is mentioning that ‘to keep those whom I have described to you in Hell forever is easy for Me (Allah).’ That is because whom He intends to do this cannot prevent himself from it and there is no one who can protect him from that, and it is not hard for Him to do whatever He intends to accomplish in terms of this, ‘And that, for Allah, is always easy,’ as the creation is His creation, and the command is His command.” [9] Jaami’ al-Bayaan. Vol.7, p.697.

The second place: In the last portion of Surah al-Ahzaab, wherein Allah, the Exalted, mentioned: “People ask you concerning the Hour. Say, "Knowledge of it is only with Allah. And what may make you perceive? Perhaps the Hour is near. Indeed, Allah has cursed the disbelievers and prepared for them a blaze. Abiding therein forever, they will not find a protector or a helper.” Al-Ahzaab: 33-35 Al-Qurtubee says: “‘They will not find a protector or a helper’ means that they will not find any protector or helper to protect them from the punishment of Allah and abiding in it forever.” [10] Al-Jaami’ li Ahkaam al-Qur’an, vol.14, p.248.

The third place: In the last part of Surah al-Jinn wherein Allah, the Exalted, stated, “And whoever disobeys Allah and His Messenger - then indeed, for him is the fire of Hell; they will abide therein forever.” Surah al-Jinn: 23 Al-Qurtubee says: “‘And whoever disobeys Allah and His Messenger,’ meaning in Tawheed (belief in Oneness of Allah) and worship. “Then indeed, for him is the fire of Hell; they will abide therein forever.” The part, “they will abide therein forever,” is in the accusative state denoting circumstances, a circumstantial adverb. The sentence refers to a singular person, however. The phrase, ‘they will remain,’ is plural because the meaning encompasses all those who do this act of disobedience. Allah brought ‘He’ as singular because of ‘whoever;’ then He pluralised the sentence at the end due to the meaning. Allah’s statement ‘forever’ indicates that the disobedience here is in the form of Shirk.” [11] Al-Jaami’ li Ahkaam al-Qur’an, vol19, p.26.
Aboo Sa`eed Al-khudree narrated that Allah's Messenger ? said, “On the Day of Resurrection, ‘Death’ will be brought forward in the shape of a black and white ram. Then a call maker will call, 'O people of Paradise!' They will stretch their necks and look carefully. The caller will say, 'Do you know this?' They will say, 'Yes, this is Death.' By then all of them will have seen it. Then he will announce again, 'O people of Hell!' They will stretch their necks and look carefully. The caller will say, 'Do you know this?' They will say, 'Yes, this is Death.' And by then, all of them will have seen it. Then it (that ram) will be slaughtered, and the caller will say, 'O people of Paradise! Eternity is for you and there is no more death and O people of Hell! Eternity is for you and there is no more death."' Then the Prophet ?, recited: And warn them of the Day of distress when the case has been decided, while (now) they are in a state of carelessness i.e., the people of the world and they do not believe.” [12] Bukhaaree (4730), it is his wording; Muslim (2849).

Al-Qurtubee states, “These narrations, due to their authenticity, are textual evidence concerning the eternal abiding of the people of Hell in it, without an end and time-limit, they will abide therein continuously, everlastingly, without experiencing death nor life, neither comfort nor deliverance. Rather, it is as He has mentioned in His Noble Book and clarified in it concerning the punishment of the disbelievers.” [13] At-Tadhkirah fi Ahwaal al-Mawta wa Umoor al-Akhirah, vol. 2, p.148. This is what Allah has organised for the disbelievers in terms of severe punishment, eternal fire, His anger and punishment.

Allah, the Exalted, mentions, “Indeed, those who disbelieve in Our ayaat - We will drive them into a fire. Every time their skins are roasted through, We will replace them with other skins so they may taste the punishment. Indeed, Allah is ever Exalted in Might and Wise.” An-Nisaa’: 56 Allah, the Sublime, also states, “And for those who disbelieve will be the fire of Hell. Death is not decreed for them1 so they may die, nor will its torment be lightened for them. Thus, do We recompense every ungrateful one. And they will cry out therein, "Our Lord, remove us;1 we will do righteousness - other than what we were doing!" But did We not grant you life enough for whoever would remember therein to remember, and the warner had come to you? So, taste the punishment, for there is not for the wrongdoers any helper.” Faatir: 36-37 Allah, the Exalted, also states, “They will say, ‘Our Lord, our wretchedness overcame us, and we were a people astray. Our Lord, remove us from it, and if we were to return to evil, we would indeed be wrongdoers.’ He will say, ‘Remain despised therein and do not speak to Me.’” Al-Mu’minoon: 106-108

3.   What also indicates the importance of knowing disbelief is that it is the counterpart of belief (Imaan) in issues concerning the divine Names and jurisprudential rulings. With what can a disobedient servant be known in this world, ‘is he a believer or a disbeliever?’ Thereafter, the need to clarify the rulings concerning him in the hereafter, ‘is he from the people of Paradise or Hell?’ Ibn Taymiyyah states, “Be aware that the issues surrounding Takfeer and rendering someone a Fasiq (disobedient) are the very issues that are related to the divine Names and creedal issues that concern the promises and warning in the abode of the hereafter. They also concern alliance and enmity, killing and innocence, and so on in the abode of this world. Allah, the Sublime, has made Paradise obligatory for the believers and prohibited for the disbelievers. These are among the universal rulings at all times and places.” [14] Majmoo’ al-Fataawaa, vol.12, p.468.

Defining Kufr (disbelief) and Riddah (apostasy)
Defining Kufr linguistically and terminologically

Kufr in linguistic terms means to cover a thing and conceal it, as if there is a cover from a person on the rights of Allah. The statement: “So-and-so committed rejection (kufr) of the bounties” is said when he conceals them and is not grateful about them. The original linguistic foundation of Kufr denotes concealment and covering. [15] Maqaayees al-Lughah, Ibn Faaris, vol.5, p.191; al-Mufradaat, ar-Ragheeb, p.714; Sharh Saheeh al-Bukhaaree, Ibn Battal, vol.8, p.383.

Kufr terminologically refers to something that is the opposite of Imaan (belief). Just as Imaan entails statement, actions, and belief, similarly, kufr also entails statement, actions, and belief and abandonment. This is a fully agreed upon position of Ahl as-Sunnah wa al-Jamaa’ah, apart from those who restricted Kufr to rejection, or rejection by heart or tongue; and negated that Kufr can happen due to Kufr-related deeds or by forgoing the genus of good deeds that are essential for the validity of Imaan, especially, the obligatory prayers. 

Ibn Taymiyyah says: “Kufr entails not believing in Allah and His Messenger, it is irrelevant whether that accompanies rejection or not. In fact, it covers unsurety, doubt, and turning away from this due to jealousy, haughtiness, and following some desires that divert from following the message.” [16] Majmoo’ al-Fataawaa, vol.12, p.468.

There are plenty of transmitted reports from the scholars stating that Kufr can be actional/practical. We mention some of them as follows:

Ishaaq ibn Raahwaih stated: “The point which the scholars have held consensus regarding in terms of excommunicating from Islam a person and ruled concerning him just as they ruled concerning a rejector is about a believer who believed in Allah, the Exalted, and in all that came from him; thereafter, he killed a prophet or helped in killing him, even if he affirms what is right and says: ‘killing prophets is prohibited,’ he is a disbeliever. Similarly, one who insults a prophet or refutes his statement without calculated deception or fear.” [17] Ta’dhheem Qadr as-Salaat, Muhammad ibn Nasr al-Marwazee, vol.2, p.930.

Al-Barbahaaree says: “We do not remove anyone from the people of the Qiblah (Muslims) from Islam unless he rejects a ayah from the Book of Allah or rejects something from the tradition of the Messenger of Allah ?, or commits sacrifice for someone else besides Allah, or prays to some else besides Allah. If he does anything of these, then it is compulsory on us to defrock him from Islam. [18] Sharh as-Sunnah, p.64.

Ibn Hazm states, “It is a description in the religion regarding one who rejects an item among the things whose belief Allah, the Exalted, has made compulsory, after the establishment of evidence against him, by arrival of truth to him, whether that rejection is done by heart and not the tongue, or by tongue and not the heart, or by both, or does an act about which clear textual evidence has mentioned that it exits him thereby from Belief (Imaan). [19] Al-Ihkaam fee Usool al-Ahkaam, vol.1, p.49.

Ibn al-Qayyim says, “Just as one becomes disbeliever by uttering a statement of disbelief by choice, which is a branch amongst the branches of disbelief, similarly, he becomes a disbeliever by doing an act which is a branch among the branches of disbelief, such as protesting to an idol and ridiculing the Mus-haf (the copy of the Noble Quran).” [20] As-Salaat wa Hukm Taarikihaa, p.55.

Defining Riddah (renouncing the faith apostasy) linguistically and terminologically

Riddah linguistically:  To deflect from a thing to something else. The source of this statement of yours is: Raddahu, Yarudduhu, riddah. Its origin points towards renegading of a thing. [21] Tahtheeb al-Lughah, al-Azharee, vol.14, p.47; as-Sihaah, al-Jawharee, vol.2, p.473; Maqaayees al-Lughah, Ibn Faaris, vol.2, p.386; al-Mufradaat, ar-Ragheeb, p.349; Mughnee al-Muhtaaj ilaa Ma’rifah Ma’aanee Alfaadh al-Minhaaj, ash-Sharbeenee, vol.5, p.427.

Riddah terminologically:  It entails breaking off the connection of Islam with the intention of disbelief or giving up the genus of good deeds on which the validity of Imaan depends, especially, the prayers; or the statement or act of disbelief, irrespective of whether he stated or did so as a ridicule, or rebelliously, or as a matter of creed.” [22] Al-Mughnee, Ibn Qudaamah, vol.1, p.238; Minhaaj at-Taalibeen, an-Nawawee, p.293; as-Saarim al-Maslool, Ibn Taymiyyah, vol.3, p.865.

Allah, the Highest, states, “And whoever among you renounces their own faith and dies a disbeliever, their deeds will become void in this life and in the Hereafter. It is they who will be the residents of the Fire. They will be there forever.” Al-Baqarah: 217 Ibn ‘Abbaas (may Allah be pleased with him) narrates that the Messenger of Allah ? stated, “Kill the one who renounces his religion.” [23] Saheeh Al-Bukhaaree (3017). Ibn ‘Abd al-Barr says, “The understanding of this hadeeth entails that one who reverts from his religion, then his blood (killing) is permissible, and his neck will be struck (will be punished by death). The entire Ummah is consensually agreed upon that.” [24] At-Tamheed lima fi al-Moowatta’ min al-Ma’aanee wa al-Asaaneed, vol.5, p.306.

Kinds of disbelief and rules concerning how to recognise them
Kufr (disbelief) are of two kinds:
1.   Kufr Akbar (major disbelief)
2.   Kufr Asghar (minor disbelief)

The major disbelief (al-Kufr al-Akbar)
The major disbelief (al-Kufr al-Akbar) invalidates the faith (Imaan), makes its committer leave Islam, makes the eternal abode in the fire imperative, and deprives the person from receiving the intercession of the intercessors. The major disbelief occurs due to creedal defects, apostatising statements and deeds, unsurety, doubt, giving up faith, turning away from it or arrogance in its regard. [25] Al-Imaan: Haqeeqatuh, Khawaarimuhu, Nawaaqiduh ‘Ind Ahl as-Sunnah, Abdullah al-Atharee, p;245.

This disbelief is of kinds, which are as follows:
1.   Kufr due to denial: That entails believing that Messengers (peace be upon them) lied.  Anyone who denies them in terms of what they brought externally or internally, then he has committed disbelief (Kufr).

The proofs for this are as follows:

Allah, the Exalted’s statement: “And who is more unjust than one who invents a lie about Allah or denies the truth when it has come to him? Is there not in Hell a sufficient residence for the disbelievers?” Al-‘Ankaboot : 68 Al-Waahidee states, “And who is more unjust than one who invents a lie about Allah,” means that ‘there is no one more unjust than the one who perceives that Allah has a partner and that He has commanded to commit immoralities! “Or denies the truth when it has come to him?” points to denying Prophet Muhammad ? and the Quran. “Is there not in Hell a sufficient residence for the disbelievers?” inferences ‘is there not in Hell an abode for this denying disbeliever?! It is a question which means confirmation.” [26] At-Tafseer al-Waseet, vol.3, p.426.

2.   Kufr of refusal and arrogance: That is when one is aware of the truthfulness of the Messenger ? and that he has brought the truth from Allah, yet he does not submit to his command and does not comply with his orders due to arrogance and rebellion.
Proofs:

Allah, the Exalted, states, “And mention when We said to the angels, "Prostrate before Adam"; so, they prostrated, except for Iblees. He refused and was arrogant and became of the disbelievers.” Al-Baqarah: 34 Allah, the Sublime, also states, “And, although their hearts were convinced the signs were true, they still denied them wrongfully and arrogantly. See then what was the end of the corruptors!”  An-Naml: 14

3.   Disbelief of doubt (Kufr ash-Shakk): That is unsurety and the state of not being totally convinced about the truthfulness of the Messengers. It is also known as disbelief based on assumption (Kufr ath-Thann), which is the opposite of certainty and surety. 
Proofs:

Allah’s statement, “Has there not reached you the news of those before you - the people of Noah and ?Aad and Thamood and those after them? No one knows them i.e., their number but Allah. Their messengers brought them clear proofs, but they returned their hands to their mouths and said, ‘Indeed, we disbelieve in that with which you have been sent, and indeed we are, about that to which you invite us, in disquieting doubt.’”  Ibraaheem: 9
Ibn Katheer states, “They stated, ‘Indeed, we disbelieve in that with which you have been sent, and indeed we are, about that to which you invite us, in disquieting doubt,’ inferring that ‘we do not believe in what you have brought because we have a strong doubt about it.’” [27] Tafseer Ibn Katheer, vol.4, p.481.

4.   Disbelief due disinclination (Kufr al-I’raad): It entails complete disinclination from the religion, that is, one disinclines totally with his hearing, heart, and knowledge from what the Messenger ? brought.
Proofs:

The Statement of Allah, the Exalted: “But those who disbelieve, from that of which they are warned, are turning away.” (Al-Ahqaaf: 3)
As-Sam’aanee says, “Allah’s statement, ‘But those who disbelieve, from that of which they are warned, are turning away,’ means they are turning away like the disinclination of those deniers who reject.” [28] Tafseer as-Sam’aanee, vol.5, p.148.

5.   Disbelief of hypocrisy (Kufr an-Nifaaq): It refers to creedal hypocrisy which entails that one reveals belief but internally conceals disbelief. Amongst its proofs is as follows:

Allah’s statement, “And of the people are some who say, ‘We believe in Allah and the Last Day,’ but they are not believers.” Al-Baqarah: 8 Ibn ‘Atiyyah says, “Allah, the Exalted, negated belief from the hypocrites.” [29] Tafseer Ibn ‘Atiyyah, vol.1, p.90.

The minor disbelief (al-Kufr al-Asghar)
Al-Kufr al-Asghar (minor disbelief) does not take one out of the fold of the religion and does not invalidate the core of the faith, however, it degrades and weakens it. Also, it does remove the attribute of Islam and its security from its committer. This is the noteworthy position amidst the scholars which is known from their statement, “a minor disbelief below the major disbelief.”
The Lawmaker has used the term (Kufr, meaning minor disbelief) on some acts of disobedience and sins for the purpose of reprimanding and threatening as they are from the characteristics of disbelief. Though, they do not reach the limit of major disbelief, however, they are amongst the major sins. They demand deserving warning and punishment without eternally reserving a place in Hellfire. The committer of this type of disbelief will be amongst those who will receive the intercession of the intercessors by the permission of Allah.
There are many different scenarios for this kind of Kufr (disbelief), amongst which are as follows:
1.   Kufr an-Ni’mah (disbelief of bounties)/ Ingratitude: That is due to his verbal attribution of the bounties to others than Allah and not in creedal terms.
Allah, the Highest, states, “They are aware of Allah’s favours, but still deny them. And most of them are ?truly? ungrateful (Kaafirs).” An-Nahl: 83 Ash-Shawkaanee says, “They recognise that the favours are from Allah, the Sublime, thereafter, they deny it due to their actions which are bad, such as worshipping someone other than Allah and also because of their statements of falsehood, wherein they say, ‘They are from Allah, however, they were attained through the intercession of the idols; and wherein they say that ‘they have inherited those favours from their fathers.’ Also, they do not utilise those favours in the pleasure of Allah and in the ways of goodness which Allah has commanded them to spend them in. It has also been stated, ‘The bounty of Allah is a reference to the prophethood of Prophet Muhammad ? which they used to acknowledge, then they began to deny his prophethood “and most of them are ungrateful/deniers,” meaning, ‘they are rejectors of the favours of Allah or they are disbelievers in Allah.’” [30] Fat-h al-Qadeer, vol.3, p.222.
Part of that is the statement a person may make: ‘If that person was not there, then such and such things would not happen,’ thus, they end up attributing the bounties to others than Him, despite of their knowledge that they are attained through the special aid granted by Allah Alone. Also, part of that is calling the children with incorrect names such as ‘Abd al-Haarith (the servant of al-Haarith), ‘Abd ar-Rasool (the servant of the Messenger), ‘Abd al-Hussein (the servant of al-Hussein) and so on.  This is incorrect because such a person has literally turned his child into the servant of someone else apart from Allah, despite the fact that He is his Creator and Conferrer of favours upon him.
2.   Ingratitude towards the life-partner and benevolence: Ibn ‘Abbaas (may Allah be pleased with him and his father) narrates that the Prophet ?: “’I was shown the Hell-fire and that the majority of its dwellers were women who were ungrateful.’ He was asked, ‘Is it because they disbelieve in Allah?’ ‘(Or are they ungrateful to Allah?)’ He replied, ‘They are ungrateful to their husbands and are ungrateful for the acts of benevolence done to them. If you have always been good (benevolent) to one of them and then she sees something in you (not of her liking), she will say, 'I have never received any good from you.’’” [31] Saheeh al-Bukhaaree (29), it is his wordings; Saheeh Muslim (907) in along hadeeth.
Aboo al-‘Abbaas al-Qurtubee says, “As for the Kufr (disbelief) that is found in Islamic Law, it entails to reject any of what is legally and essentially known from it. That is what the religious/legal convention has contextualised. The word Kufr has also come in the meaning of rejecting the Giver of favours, ingratitude towards the favours and giving up caring about the rights, whence, the Prophet’s statement to the women, ‘They are ungrateful for the acts of benevolence and ungrateful to their husbands,’ meaning that ‘they deny the rights of their husbands as well as their benevolence. Hence, it is appropriate to say: ‘Kufr doona kufr was thulm doona thulm,’ ‘There is a kufr (ingratitude) which is below the real kufr (disbelief) and there is a minor injustice which is below the major injustice.’” [32] Al-Mufhim lima Ashkala min Talkhees Kitaab Muslim, vol.1, p.253.
3.   Swearing by other than Allah: Ibn ‘Umar (may Allah be pleased with him and his father) narrates that the Prophet ? stated: “One who swears by other than Allah, then he has committed an act of Kufr (disbelief) or Shirk (polytheism).” [33] Aboo Dawood (3251); at-Tirmithee (1535), his wordings; Ahmad (6072). It was authenticiated by Ibn Hibaan in his Saheeh Collection (4358), al-Haakim in al-Musatdrak (7814) and commented: It is according to the conditions of al-Bukhaaree and Muslim, Ibn Taymiyyah as quoted in al-Mustadrak ‘Alaa Majmoo’ al-Fataawa by Ibn al-Qaasim (1/281), Ibn al-Qayyim in alWaabil al-Sayyib (189), Ibn Baaz in Mahmo’’ al-Fatwaawa (3/144), al-Albaanee in Saheeh Sunan al-Tirmithee (1535), al-Waadi’ee in al-Saheeh al-Musnad (734) and commented: It is according to the conditions of Muslim, and Shu’ayb al-Arna’oot in his Takhreej of Musnad Ahmad (6072).
The scholars of Ahl as-Sunnah wa al-Jamaa’ah have affirmed this kind of Kufr and Shirk is minor which does not take their committer out of the fold of Islam, as long as the item one swears by is not magnified in the heart of the swearer to the same level as the magnification and greatness of Allah. [34] Tarh at-Tathreeb fi Sharh at-Taqreeb, al-‘Iraaqee, vol.7, p.142-147.
An-Nawawee says, “If the one taking an oath believes in the greatness of the object he swears by, what he believes concerning Allah, then he has committed disbelief.” [35] Rawdah al-Taalibeen wa ‘Umdah al-Mufteen, vol.11, p.6.
Ibn Uthaymeen states, “To swear by other than Allah is a major Shirk, when one believes that the thing he swears by is equal to Allah in greatness and magnification, otherwise, it will be considered as a minor Shirk.” [36] Al-Qawl al-Mufeed, vol.2, p.325.
4.   Fighting with a Muslim: Ibn Mas’ood (may Allah be pleased with him) narrates that the Prophet ? stated: ‘Insulting a Muslim is an act of disobedience and fighting with him is an act of Kufr.” [37] Saheeh Bukhaaree (48); Saheeh Muslim (64).
An-Nawawee says, “His fighting without any right does not warrant branding him with Kufr according to the people of the Truth, such that it removes him from the religion, as we have mentioned previously in many other places, unless if he thinks that to be permissible.” [38] Sharh an-Nawawee ‘ala Muslim, vol.2, p.53.
At-Tibee says, “The meaning of the hadeeth refers to the statement of the Prophet ?: ‘A Muslim is who from whose tongues and hands other Muslims are safe.’ [39] Saheeh Al-Bukhaaree (10) and the wording is his and is long; and Saheeh Muslim (40) from the hadeeth of Abdullah bin ‘Amr, may Allah be pleased with them; Saheeh Muslim (41) from the hadeeth of Jaabir bin Abdullah, may Allah be pleased with them. It has been confirmed that the referred Muslim here is the one who is complete in his faith (Imaan) and accomplishes his rights as much as he can. The referral to the Kufr in this hadeeth is indicative of a decrease in his faith intensely.” [40] See: Sharh Al-Mishkaat, vol.10, p. 3112.
Thus, this kind of Kufr does not remove one from the religion as per the agreement of all Imaams [41] See: Al-Imaan, Al-Qaasim bin Salaam, p. 43-46; At-Tamheed, Ibn Abd Al-Bar vol.4, p.236. ; such committers have not lost the attributes of Imaan (faith) due to the statement of Allah, “And if two factions among the believers should fight, then make settlement between the two.” Al-Hujuraat: 9

5.   Slandering someone’s lineage and lamenting the dead: Aboo Hurayrah (may Allah be pleased with him) narrated that the Prophet ? stated, “There are two characteristics that are found in people which are tantamount to Kufr, slandering one's lineage and lamenting the dead.” [42] Saheeh Muslim (67).
Ibn Taymiyyah says, “These two characteristics are found in people. The characteristics per se are an act of disbelief in the sense that they were the acts of the disbelievers. They are found in people; however, it is not that everyone in whom any branch amongst the branches of Kufr is found becomes a disbeliever with absolute disbelief to the extent that the reality of disbelief is now found in him; just as, not everyone in whom a branch amongst the branches of Imaan (faith) is found becomes a believer to the extent that the main root of Imaan is now found in him.” [43] See: Iqtidaa’ Siraat al-Mustaqeem li Mukhalaafat Ashaab al-Jaheem, Requiring the Straight Path to Dissent from the Companions of Hell, vol.1, p,237.
6.   Attribution of lineage to other than the father: Aboo Tharr (may Allah be pleased with him) narrates that the Prophet ? stated, “A person who attributes his lineage to anyone other than his real father, knowing this is not the case, commits an act of disbelief. And he who makes a claim about a people concerning that which is not found in them, is none of us. He should make his abode in Hell.” [44] Saheeh Al-Bukhaaree (3508), the wording is his, and Saheeh Muslim (61).
‘Alee al-Qaaree says, “‘He commits an act of disbelief’ means that he has gotten closer to disbelief, or there is fear of disbelief concerning him. In al-Nihaayah: ‘ad-Di’wah, with kasrah, when it concerns lineage, then it signifies a person’s attribution of lineage to someone other than his father and other than his kinsfolk. They (Arabs) used to do that; thus, they were prohibited from doing it. It is Haram (prohibited) to claim lineage to someone else other than the real father knowingly. One who thinks this is to be allowed, then he has committed an act of disbelief due to his opposition to the consensus. As for one who does not believe in that, then in that regard, the meaning that ‘he committed an act of disbelief’ will be read in two ways. Firstly, his act resembles the act of the disbelievers.  Secondly, he is the denier (ungrateful) of the bounties of Islam.” [45] See: Mirqaat al-Mafateeh Sharh Mishkaat al-Masabeeh, (5/2170).
There are many kinds of minor disbelief which is impossible to cover them all. Ibn Battah mentioned several kinds of them, and he placed a chapter for them, titled: ‘Chapter concerning mentioning the sins that take their committer to the level of disbelief that does not remove him from the religion.’ [46] See: Al-Ibaanah al-Kubraa (2/723).

The guidelines regarding the differentiation between the major and minor Kufr
The major Shirk and Kufr that removes a person from the religion are that which invalidates the foundation of the religion, namely the Oneness of Allah and overall adherence to Islamic Law in general terms. As for the minor Shirk and Kufr, they are below that in terms of the fact that they do not invalidate the foundation of the religion and neither are they from those minor faults that have been pardoned; as Allah, the Exalted, has stated, “If you avoid the major sins which you are forbidden, We will remove from you your lesser sins and admit you to a noble entrance into Paradise.” An-Nisaa’: 31
Ash-Shawkaanee states, “It means, ‘If you refrain from the major sins which Allah has prohibited for you, then we will expiate your sins from you, that is, those sins which are minor.’” [47] See: Fath Al-Qadeer (1/527).
Every sin which has been established to be Shirk, however, have proofs which indicate that it is not that Shirk which removes one from the religion, then that Shirk is a minor Shirk. And Every sin which has been established to be Kufr, however, the proofs indicate that it is not that Kufr which removes one from the religion, then that Kufr is a minor Kufr.
Aboo ‘Ubayd al-Qaasim ibn Salaam says, “As for the narrations that report Kufr and Shirk and their necessary occurrence due to the sins, their meaning according to us is that they do not establish those Kufr and Shirk on their doers which remove them from Imaan. Their necessary occurrence is only to highlight that they are part of the morals and ways which have been adopted by the disbelievers and polytheists.” [48] See: Al-Imaan, p. 43.
As for the minor Shirk, that is like showing off, as there is textual evidence from the Messenger of Allah ?. That is because the act in itself should have been only for Allah, however, Shirk has been inserted to beautify it for the people.
As for the minor Kufr, it is like judging outside the Islamic legal framework in a specific case by empowering the human desires and by thinking that is permissible. That is the exegesis of ‘Ibn Abbaas regarding the statement of Allah, “And whoever does not judge by what Allah has revealed - then it is those who are the disbelievers.”  Al-Maa’idah: 44, wherein he said, “This is not that Kufr which people go towards.” [49] See: Tafseer Ibn Abee Haatim, p.6434. As for the complete refusal of Islamic Law and the legislation of man-made laws, then that is a major Kufr. The indication of the ayah towards the major Kufr according to the valid view is what has originally been aimed at. The statement of Ibn ‘Abbaas does not invalidate that view and does not prevent a ruler who has judged in a particular case against Islamic Law due to the desires to be entered into the term of Kufr, however, considering that to be a minor Kufr.
Ibn al-Qayyim says, “The correct view is that judging against what Allah has revealed covers both types of Kufr, the minor and the major Kufr, according to the circumstances of the ruler. If he believes that it is imperative to pass judgement according to what Allah has revealed in that particular event, yet he turns away from that by disobedience, while acknowledging that he deserves punishment, then in that case, this will be a minor Kufr. If he believes that it is not obligatory to follow the divine Law and that he has a choice in that regard, while being certain that that is the command of Allah, then this will be a major Kufr. If he was ignorant and committed a mistake, then he is a doer of error and he enters into the rule concerning error-makers.” [50] See: Madaarij as-Saalikeen, vol.1, p.346.
Ibn ‘Uthaymeen states, “As for the Prophet’s statement ‘towards Him is the judgement,’ [51] Sunan Aboo Dawood (4955) and Sunan an-Nasaa’ee (5387) at length from the hadeeth of Haanee bin Yazeed (may Allah be pleased with him). It was authenticated by Ibn Hibbaan in his Saheeh (504), and by al-Albaanee in “Saheeh Sunan Abee Dawood” (4955), and Al-Waadi’ee graded it as authentic in “As-Saheeh al-Musnad” (1197), and Shuayb Al-Arnaa’oot included its chain of transmission in Takhreej Sunan Abee Dawood (4955). Ibn Baaz said in “Sharh Kitaab al-Tawheed” (three hundred): there is some dispute as to how authentic it is. that indicates that anyone who turns a judgement to someone other than Allah, then he has committed Shirk.  … It is incumbent upon a student of knowledge to know the difference between the legislation that turned into a system to be followed and to replace the Quran and between that one who judges in a particular case without what Allah has revealed, then that can be an act of disbelief, disobedience or injustice.” [52] See: Al-Qawl al-Mufeed ‘ala Kitaab at-Tawheed, vol.2, p.265.
The minor Shirk is amongst the major sins and they are of ranks, wherein some are greater than the others, as it has been narrated in the hadeeth of Aboo Bakrah (may Allah be pleased with him), that the Prophet ? stated, “Shall I not inform you of the greatest of the major sins? They are to seek partners with Allah (Shirk), disobedience to parents, … .” [53] Saheeh Al-Bukhaaree (2654) and Saheeh Muslim (87).
The principle in this regard is that the words of Kufr and Shirk cited in the Book of Allah and the Sunnah, and especially those which have the definite particles alif and laam, should be kept on their absolute reality and their absolute meaning, that is to say, that they remove one from the religion, until there appears a proof that prevents that and requires that the minor Kufr and major Kufr are meant there.
‘Abd al-Lateef ibn ‘Abd ar-Rahmaan Aal ash-Shaikh states, “The words injustice, sin, disobedience, immoral sin, illegal alliance, enmity, inclination towards the wrongdoers, Shirk, and so on amongst the words that have come in the Book and the Sunnah, can mean what they really stand for in absolute terms and their absolute reality, and they can also stand for the absolute reality. The former usage is the principle according to the jurisconsults. The latter usage can only be considered if there is a literal or significant indicium concerning it. That can only be known through the Prophetic elaboration or through the explanation of the Sunnah. Allah, the Exalted, states, “And We have not sent a messenger except in the language of his people to clarify the message for them.” Ibraaheem: 4 [54] See: Ar-Rasaa’il al-Mufeedah, Abdul Lateef Aal ash-Shaykh, p. 12.
What indicates that that is the principle towards which hastens to the human mind, as it is in the hadeeth of Ibn ‘Abbaas (may Allah be pleased with him) concerning the story about the solar eclipse and the statement of the Prophet ?: “I was shown the Hellfire and have not seen such a horrible scene before like that day and I saw its most dwellers as women. The companions asked, ‘Why, O Messenger of Allah?’ He replied, ‘Because of their ingratitude (kufr).’ He was asked, ‘Are they ungrateful to (commit kufr against) Allah?’ He replied, ‘They are ungrateful to their husbands and to the benevolence.’ If you show goodness to anyone of them all the time, thereafter, she sees something disliked from you, she says, ‘I have never seen anything good from you.’” [55] Saheeh Al-Bukhaaree (1052), the wording is his, and Saheeh Muslim (907).
There are indications which confirm that the meaning Kufr or Shirk mentioned in the Quranic or Prophetic texts is the minor one and not the major one. Among them are as follows:
1.   Explicit mention by the text itself or by the indication of other textual proofs. These provide the strongest indications:
Example:  Inference made by the text indicating that the Shirk mentioned therein is the minor one and not the major one:
It is narrated on the authority of Mahmood ibn Labeed (may Allah be pleased with him) that the Prophet ? stated: “The greatest thing that I fear upon you is the minor Shirk.’ They asked: ‘O Messenger of Allah! What is the minor Shirk?’ He replied, ‘Ostentation.” [56] Musnad Ahmad (23630) and the wording is his, and Al-Bayhaqee in “Shu`ab Al-Imaan” (6831).  It was authenticated by Ibn Baaz in “Majmoo’ al-Fataawaa” (2/29) and by al-Albaanee in “Saheeh al-Jaami’” (1555), and Shuayb al-Arnaa’oot graded it as authentic in his “Musnad Ahmad” (23630), and its chain of transmission was improved by Ibn Hajar in “Buloogh Al-Maraam” (440), and Al-Munthiree found it sound in “Al-Targheeb wat-Tarheeb” (1/52), and al-‘Iraaqee authenticated its men in “Takhreej Al-Ihyaa’” (3/361), and Al-Haythamee said in “Majmaa’ Al-Zawaa’id” (1 /107): Its narrators are from the narrators found in the Saheeh Books..
Al-Hussein ibn Muhammad al-Maghribee says, “Naming it the minor Shirk indicates that it is in a rank that is next to the major Shirk which is the great injustice and destructive, detrimental consequence.” [57] See: Al-Badr At-Tamaam Sharh Buloogh Al-Maraam, vol.10, p.267.
The example wherein some of the textual proofs indicate the mentioned Shirk is the minor one and not the major one:
The hadeeth of Ibn ‘Umar (may Allah be pleased with him), wherein the Prophet ?: “Do not revert to disbelief after me by striking (cutting) the necks of one another.” [58] Al-Bukhaaree (7077), the wording is his, and Muslim (66). Combine this with the statement of Allah, the Exalted, “And if two factions among the believers should fight, then make settlement between the two.” al-Hujuraat: 9 Allah called the fighting factions believers, which is indicative that the Kufr herein mentioned in the hadeeth, it is not the Kufr that removes one from the religion.
2.   Another point that indicates that the meaning of Shirk or Kufr in the legal texts is the minor one, is that the punishment of renouncing the faith is not subsequently imposed on its doer, although the punishment of disobeyers may be established such as in the case of a fornicator and thief, coupled with the negation of faith from them.

3.   Among the indications about the minor Shirk or Kufr is that their words appear as indefinite nouns and not definite nouns. If the noun appears with a definite article (Alif Laam), then it indicates that the objective is the Kufr that removes one from the religion.  
Ibn Taymiyyah states, “There is a difference between the Kufr that is definite with the particle Alif Laam and between the Kufr that is indefinite in terms of establishing the fact.” [59] Iqtidaa’ as-Siraat al-Mustaqeem li Mukhaalafah Ashaab al-jaheem, vol.1, p.237.
Ibn Baaz states, “The absolute Kufr which is definite through the particle of definiteness such as the statement of the Prophet ?, “The difference between a person and between ‘the’ Kufr and ‘the’ Shirk is giving up prayers.’ [60] Muslim (82) with a slight difference from the hadeeth of Jaabir bin Abdullah, may Allah be pleased with them. It is the major Kufr herein referred, according to the soundest of the two statements of the scholars.” [61] See: Majmoo’ Fataawaa Bin Baaz, (3/452).

4.   What is also indicative that the Shirk or Kufr being minor is how the Companions (may Allah be pleased with them) understood the sacred texts. The example for that:
The hadeeth of Ibn Mas’ood (may Allah be pleased with him), wherein the Prophet ? stated, “‘Bad omen is an act of Shirk.’ None of us but he is affected by it, however, Allah removes its influence by relying on Him.” [62] Sunan Aboo Dawood (3910), Sunan At-Tirmithee (1614) with little difference, Sunan Ibn Maajah (3538), and Musnad Ahmad (3687) and the wording belong to the narration of the two latter ones. At-Tirmithee said: It is Hasan Saheeh (good authentic). It was authenticated by Ibn Hibbaan in his Saheeh (6122), Ibn al-Arabee in Aaridah al-Ahwathee (4/108), Ibn Daqeeq in al-Iqtiraah (125), and al-Albaanee in Saheeh Sunan Abee Dawood. (3910), al-Waadi’ee in “Al-Saheeh Al-Musnad” (876), and Ahmad Shaakir in his commentary of “Musnad Ahmad” (6/110), and Shuayb Al-Arna’ut in “Sunan Abee Dawood” (3910) authenticated it.  At-Tahawi said in “Sharh Ma’aanee Al-Athaar” (4/312): The narrations have been narrated at a Mutawaatir frequency. Al-Bukhaaree said: “Sulaymaan ibn Harb used to reject the part “None of us but…” and state that Prophet ? never said it. He said: This seems to be from the words of Ibn Mas’ood” Al-‘Ilal al-Kabeer of at-Tirmithee (266). ‘Abd al-Haq al-Ishbeelee said in al-Ahkaam al-Sughraa (521): “ It is said that the part “None of us but…” was from the words of Ibn Mas’ood. Ibn al-Qayyim aid in Madaarij al-Saalikeen (3/373): “It is found in Saheeh al-Bukhaaree and Saheeh Muslim.; and this addition “None of us but…” is incorporated into the narration of Ibn Mas’ood; Ibn Hajar said in al-Nukat (2/826): The verdict on this part “None of us but…” is that it is certainly added to the text of the hadeeth.”. The last portion of the hadeeth, ‘None of us but he is affected by it, however, Allah removes its influence by relying on Him,’ is an inserted statement of Ibn Mas’ood, whose meaning is, ‘There is none among us, but he is afflicted by bad omen.’ [63] Ma’aalim As-Sunan, Al-Khattaabee, vol.4, p.232.
Al-Math-haree says, “’Bad omen is an act of Shirk’ entails that Allah Alone is the one who benefits and harms; the one who facilitates and who places hardships. Hence, if anyone believes that someone or something besides Allah gives benefit or harm, facilitation or hardship; then he has taken someone else as partner to Allah. Al-Bukhaaree states that Sulaymaan ibn Harb said that the statement, ‘None of us but …’ is not the statement of the Prophet ?, instead, it is the statement of Ibn Mas’ood. The meaning of that is, ‘None of us but in his heart, there contains bad omen.’ That signifies that ‘our hearts were like the hearts of the people of the time of ignorance in believing that bad omen does influence.  However, when we started to rely in Allah, to accept the hadeeth of His Messenger and believed in its truthfulness; then Allah removed from us the belief of the people of the time of ignorance and placed in our hearts the Sunnah and following the Truth.” [64] Al-Mafaateeh fi Sharh al-Masaabeeh, vol.5, p.92.
Kufr (disbelief) can be through verbal statement, or act just as it can be through belief
The overall statements of the scholars can be summarised in five sentences:
1.   Kufr can occur due to the statement or act, they did not stipulate the belief in this regard.
2.   Kufr can be verbally or through one’s act or belief, they varied between these.
3.   Kufr can be through a verbal pronouncement or act, if it is not something that is believed in.  They explicitly mentioned about the non-requirement of belief for that.
4.   Kufr can occur through a verbal utterance or act, even if it is due to a worldly fortune.
5.   Rebuffs and rebuttals against the Jahmiyyah and Murji’ah who only stipulate belief or making a divine prohibition permissible.
One who ponders over these sentences will find their import is the same, though some sentences are more explicit than others in clarifying the objective. [65] At-Tawassut, wa al-Iqtisaad fee anna al kufr yakoonu bi al-Qawl aw al-Fi’l aw al-I’tiqaad, Alawee As-Saqqaaf, p.16, 25 - 148.
This is an overview of their statements which affirms that they all agree that Kufr can be either an utterance or an act as it can be a belief. 
1.   Muhammad ibn Idrees ash-Shaafi’ee (d. 204 AH) was asked concerning a person who pokes fun of a ayah amongst the ayaat of Allah. He replied. ‘He is a disbeliever.’ He then used the following statement of Allah, the Exalted, as a proof, “Say, O Muhammad. ‘Were you really deriding Allah, His ayaat and His Messenger? Do not give excuses, you have definitely committed disbelief after embracing your faith.” [66] See: “Al-Saarim Al-Maslool”, Ibn Taymiyyah, (3/956).
2.   Ishaaq ibn Raahwaih al-Marwazee (d. 238 AH) said, “Amongst the persons upon whose Takfeer they agreed on and concerning whom they issued the same ruling as the one for the rejector is that believer who believed in Allah and in what came from Him, thereafter, he killed a prophet or assisted in killing him, even if he affirms and says, ‘Killing a prophet is prohibited. Likewise, one abuses a prophet or rejects his statement without practicing taqiyyah (protective dissimulation) and without being driven by fear.” [67] Ta’theem Qadr as-Salaat, al-Marwazee, (2/930). And his saying: without Taqiyyah and no fear, meaning, without compulsion.
3.   Aboo Thaur Ibraaheem ibn Khaalid (d. 240 AH) says, “Know, may Allah have mercy on us and you, that Imaan (faith) is an affirmation inside the heart, statement by tongue, and practice by limbs. That is because there is no dispute among the people of knowledge concerning a person who says. ‘I bear witness that Allah is One, and that what the Messengers brought is true’ and he professes faith all the divinely revealed Laws, thereafter he says, ‘My heart is not convinced about a thing amongst the items of faith, and I do not affirm it,’ then he is not a Muslim. If he says, ‘Messiah (Jesus) is God,’ and rejects the position of Islam, and says, ‘My heart is not convinced about a thing among the items of faith,’ then he is a disbeliever for revealing that, and he is not a believer. [68] See: Sharh Usool ‘Itiqaad Ahl as-Sunnah wal-Jama’ah” by al-Laalka’ee (4/849).
4.   Ahmad ibn Hanbal (d. 241 AH), in his refutation against al-Jahm, said, “It requires him to say, ‘When a person affirms the faith, thereafter, he wears a cincture around his waist, prays toward the cross, goes to the churches, monasteries, and commits all major sins, yet he still affirms the faith despite all that, according to him (al-Jahm), he is still a believer. [69] That is, according to Ahmad, he is not a believer. These things are among the repulsive statements that accompanies them.” [70] See: Al-Imaan (Faith), Ibn Taymiyyah, p.384.
‘Abdullah ibn Ahmad ibn Hanbal says, “I asked my father concerning a man who says to another man, ‘O son of so-and-so and son of the one who created!’ My father replied, ‘This person has renounced Islam.’ I asked my father, ‘Should his neck be struck with a sword.’ My father replied, ‘Yes, his neck should be struck.’” [71] See: “Masaa’il Imaam Ahmad,” the narration of his son Abdullah (3/1291).
5.   Aboo Muhammad ‘‘Alee ibn Hazm al-Thaahiree (d. 456 AH) says, “To reject a thing concerning which the evidence is authentically sound, that ‘there is no faith without its affirmation,’ then its rejection is an act of disbelief. Similarly, to utter a thing amongst all those things concerning which clear evidence is established, that its utterance is an act of disbelief, then that will signify disbelief. Likewise, to act upon a thing amongst those things concerning which explicit evidence is firmly established, that doing so amounts to disbelief, then it will mean disbelief. Disbelief increases. Any increase thereof will also signify disbelief. Disbelief decreases as well. Overall, whatever remains thereof or reduces thereof, it is all disbelief.  Some forms of disbelief are greater, more severe and worse than others, yet all of them are an act of disbelief.” [72] Al-Fasl fee Fil al-Milal wa al-Ahwaa wa an-Nahl, (3/244).
6.   Qaadee Aboo Bakr ibn al-‘Arabee al-Maalikee (d. 543 AH):  Ibn al-‘Arabee states in his exegesis of the statement of Allah, the Exalted, ‘And if you ask them, they will surely say, ‘We were only conversing and playing,’’ adding, “What they stated can either be a serious statement or a mere joke. In either case, it is an act of disbelief. Utterances made jokingly by not being serious is also an act of disbelief, there is dispute concerning it among the scholars of the Ummah.” [73] Ahkaam al-Qur’an, (2/976).
7.   ‘Iyaad ibn Moosa al-Maalikee (d. 544 AH) states, “We definitely conclude concerning the Takfeer of every utterer of a statement that contributes to make the Ummah astray and to excommunicate from Islam all the Companions …. Likewise, we excommunicated from Islam a person due to an act that the Muslims are agreed upon that it can only emanate from a disbeliever, even if its committer explicitly portrays to follow Islam; all of which is due to his act such as prostrating before an idol, or sun or moon, cross or fire, going to churches and monasteries with their adherents and wearing their religious attire such as wearing a cincture, tonsuring (shaving all or part of the hair on the scalp as a sign of Christian religious devotion in some medieval Catholic and Eastern Orthodox churches) [74] Mulla ‘Alee al-Qaaree commented in his book “Sharh ash-Shifaa’” by saying, “Perhaps the meaning of ‘fahs’ of the head - meaning: to shave its middle - was a symbol of disbelief before that, but now it has become abundant among Muslims, hence, it is not considered blasphemy now.” ; the Muslims have held a consensus that these acts are only found in disbelievers and that these acts are a sign which is indicative of disbelief [75] Rather, it is disbelief in itself. Some of the scholars from whom Takfeer was transmitted by word or deed, justified that with terms not known to the Salaf, which indicate their influence on the Murji’ah; Like their saying: This action is not blasphemy, but it indicates blasphemy, or a sign of disbelief. See: The sixth introduction of the book, Al-Tawassut wa al-Iqtisad by Alawee As-Saqqaaf. , even if their doer explicitly portrays to follow Islam.” [76] Ash-Shifaa bi Ta’reef Huqooq al-Mustafaa, (2/396). See the title: How he did not stipulate the word or the deed with belief?
8.   Fakhr ad-Deen Muhammad ibn ‘Umar ar-Raazi ash-Shaafi’ee (d. 606 AH) states in his exegesis of the statement of Allah, “And if you ask them, they will surely say, "We were only conversing and playing." Say, "Is it Allah and His ayaat and His Messenger that you were mocking? Make no excuse; you have disbelieved i.e., rejected faith after your belief.” at-Tawbah: 65-66, adding. “The third issue concerns the statement of Allah, the Exalted, ‘you have disbelieved i.e., rejected faith after your belief,’ which refers to a few issues which are as follows:
The first issue: To deride the religion in whatever form is an act of disbelief in Allah. That is because derision signifies belittlement. Whereas the greatest supporting principle in belief is to exalt Allah as much as possible, thus, to correlate between the two is impossible.
The second issue: The ayah indicates the invalidity of the statement of the one who says, ‘Disbelief only concerns the internal acts of the hearts.’
The third issue: It also indicates that the statement that emanated from them was an act of disbelief, even if they were hypocrites before, and that disbelief can occur anew from time to time.
The fourth issue: It infers that disbelief occurred after they were believers.” [77] Tafseer Ar-Raazee, (16/95).
9.   ‘Abdullah ibn Ahmad ibn Qudaamah al-Maqdisee al-Hanbalee (d. 620 AH) comments about the one who renounces his faith for a while, “His fast is invalidated and it is imperative for him to make up for the fast of that day when he returns to Islam, irrespective of the fact whether he re-entered Islam during the same day or after the day passing; or his renouncement was due to his belief of those items that warrant excommunication from Islam, or due to his doubt concerning the things that demand excommunication from Islam on the basis of doubt; or due to his utterance of the words of disbelief out of derision or otherwise. Allah, the Exalted, says, “And if you ask them, they will surely say, ‘We were only conversing and playing.’ Say, ‘Is it Allah and His ayaat and His Messenger that you were mocking? Make no excuse; you have disbelieved i.e., rejected faith after your belief.’” at-Tawbah: 65-66 That is because fasting is an act of worship whose condition is also making an intention. Renouncement of faith invalidated that, just as is the case concerning the obligatory prayers and Hajj. Also, because it is an act of worship per se, which the disbelief negated like the obligatory prayers.” [78] See: Al-Mughnee, (4/370), according to him apostasy is by belief, and it is by uttering the word unbelief.

10. Muhyyi ad-Deen Yahya ibn Sharaf an-Nawawee ash-Shaafi’ee (d. 676 AH) says concerning renouncing the religion, “That entails breaking off ties with Islam. That can sometimes happen due to uttering a word of disbelief, and sometimes due to the acts committed. The acts that demand disbelief are those that emanate deliberately or by derision in explicit terms such as prostrating before an idol or the sun, placing a copy of the Noble Quran into dust bins (filthy places), sorcery that involves worshipping the sun and the likes. The Imam states in some of the commentaries whilst quoting my Sheikh, ‘An act per se cannot be classed as disbelief.’ He says, ‘This is a major error from the commentator. I mentioned so to notify about his mistake. Renouncement of the faith (Riddah) occurs by making a statement of disbelief, irrespective of whether that came out due to a belief, rebellion or derision.” [79] See: Rawdah at-Taalibeen, (7/283).
11. Ahmad ibn ‘Abd al-Haleem ibn Taymiyyah (d. 728 AH) says, “One who utters a statement of disbelief unnecessarily, deliberately, and knowingly that it is an utterance of disbelief; in that case he has committed disbelief internally and externally. Because we do not permit saying, ‘That internally he is still a believer.’ One who says that, then he has abjured Islam. Allah, the Sublime, states, ‘Whoever disbelieves in i.e., denies Allah after his belief, except for one who is forced to renounce his religion while his heart is secure in faith. But those who willingly open their breasts to disbelief, upon them is wrath from Allah, and for them is a great punishment.’ an-Nahl: 106 It is well known that Allah did not mean by disbelief, the belief in the heart only, because this is something internal which a person cannot be forced to forgo, while He has exempted the one who has been forced. He did not mean the one who says and believes as He exempted the one who has been forced, while he is not forced into the belief and statement. One can only be forced into the statement. Thus, it has been known the He meant thereby the one who utters the statement of disbelief. The wrath of Allah is upon him and from him awaits a painful punishment, and that he is a disbeliever due to that; except for one who is forced to renounce his religion while he is secure in faith. But the who willingly opens his breasts to disbelief amongst those who are forced, then he is also a disbeliever.  Thus, one who utters the statement of disbelief becomes a disbeliever, except for the one who is forced to do that, while his heart is secure and content with belief. Allah, the Exalted mentioned concerning those who deride, “Do not give excuses today, you have already committed disbelief after your having your faith,” [80] See: Al-Saarim Al-Maslool, p. 524.
He also said, “Allah, the Sublime, states ‘But they i.e., the hypocrites say, ‘We have believed in Allah and in the Messenger, and we obey’; then a party of them turns away after that. And those are not believers. And when they are called to the words of Allah and His Messenger to judge between them, at once a party of them turns aside in refusal. But if the right is theirs, they come to him in prompt obedience. Is there disease in their hearts? Or have they doubted? Or do they fear that Allah will be unjust to them, or His Messenger? Rather, it is they who are the wrongdoers i.e., the unjust. The only statement of the true believers when they are called to Allah and His Messenger to judge between them is that they say, ‘We hear, and we obey.’ And those are the successful.’ an-Noor: 47-51 Allah, the Exalted, clarified that one who turns away from the obedience of the Messenger, relinquishes his command; then he is amongst the hypocrites, and he is not a believer.  Whereas a believer is he who says, ‘We hear, and we obey.’ When hypocrisy is established and faith disappears with relinquishing the command of the Messenger and the intention of taking the matter to someone else for the judgement, notwithstanding, that that is a mere abandonment. Moreover, the reason for that could be the strong desires. Then what about reviling, abusing and so on?!” [81] See: Al-Saarim Al-Maslool, p. 43.

12. Muhammad ibn Aboo Bakr ibn Qayyim al-Jawziyyah (d. 751 AH): Ibn al-Qayyim states, “The branches of faith (Imaan) are of two kinds, verbal and actional. Among the verbal branches of faith, there is a branch whose disappearance obligates the extinction of faith. Likewise, among the actional branches of faith, there is that part whose disappearance necessitates the extinction of faith. Similar is the case with the actional and verbal branches of disbelief (Kufr). Just as pronouncing a statement of disbelief intentionally turns a person into a disbeliever, as that is a branch among the branches of disbelief, likewise, a person becomes a disbeliever by doing an act of a branch among the branches of disbelief, such as prostrating to an idol or debasing the copy of the Quran. This is the crucial principle.” [82] See: Kitaab as-Salaat, p. 53, 54.

13. Taqee ad-Deen ‘‘Alee ibn Abd al-Kaafee as-Subkee ash-Shaafi’ee (d. 756 AH) states, “Takfeer is a religio-legal injunction whose cause is the rejection of the Lordship or the Oneness of Allah, the divine message, a statement or an act the Lawgiver has deemed it to be an act of disbelief, even if the latter does not entail rejection.” [83] See: Fataawaa As-Subkee, (2/586).

14. Muhammad ibn ‘Abd al-Wahhaab at-Tameemee (d. 1206 AH) states, “Know, may Allah have mercy on you, that the religion of Allah is imposed on the heart by harbouring belief, love, and hatred; on the tongue by pronouncing belief, and avoiding pronouncing disbelief; on the limbs by accomplishing the pillars of Islam and refraining from doing those acts that excommunicated a person from Islam. If any of these three things becomes defective, then one disbelieves and renounces the faith.
The example of the act related to the heart: That one thinks that this certain belief which most people hold concerning the living and the dead is ultimately true, and he uses the majority holding that belief as a proof for that, then he is a disbeliever, rejector of the Prophet ?, even if he does not say that by his tongue and only acts upon the beliefs of Tawheed. Similarly, when one doubts, does not know who holds the truth; though he has not rejected, however, he has not affirmed the Prophet ? either. He is, in other words, saying, ‘Hopefully, Allah will clarify the truth!’ He is thereby in doubt. Thus, he is a renouncer of faith, even if he has always spoken about the beliefs of Tawheed.
The example concerning the utterance by the tongue: That one believes in the truth, loves it, rejects the falsehood and detests it, however, he spoke by appeasing the people of al-Ahsaa or the people of Makkah or other, in compliance with them due to the fear of their evil; either by writing to them a statement by praising the ways that they follow, or mentions that he has abandoned his way, thinking that he is scheming against them, while his heart is certain that this act of his does not harm him in terms of belief. And this is again due to his delusion!
That is what the meaning of the statement of Allah, the Exalted, entails: ‘Whoever disbelieves in Allah after his belief, except for one who is forced to renounce his religion while his heart is secure in faith, An-Nahl up to His statement, ‘That is because they preferred the worldly life over the Hereafter.’ An-Nahl: 107 The only reason for that happening is that there is a change in the beliefs.
One who understands this will recognise that there is a significant and great risk in this and will comprehend the dire need to learn and study. And this is meaning of His statement concerning the dissuasion from renouncing the faith, verbally, through belief, due to doubt or through actions. And Allah knows the best.” [84] See: Ad-Durar As-Sanniyyah, (10/87).
 
15. The Permanent Committee for Scholarly Research and Iftaa (Saudi Arabia): In the Fatwas issued by the Permanent Committee, the following has been mentioned:
“Question: It is stated that the renouncement of faith can be actional or verbal. What are the kinds of actional, verbal, and creed-related renouncement? Please if you can clarify that to me briefly and clearly.
All praises are due to Allah, and peace and salutations of Allah be upon His Messenger, family, and companions.  Thereafter:
Answer: Riddah (renouncing the faith) can be through utterance, action, belief, and doubt. Thus, whoever ascribes a partner to Allah, rejects His Lordship, Oneness, attribute out of all of His attributes, some of His Books, some of His Messengers, insults Allah, His Messenger; rejects a thing from the prohibited things upon whose prohibition there is an established consensus, deems it permissible; or denies a pillar amongst the five pillars of Islam, or doubts in its obligation or in the truthfulness of Prophet Muhamamd ? or of anyone apart from him amongst the prophets; or doubts in the resurrection; or prostrates to an idol, a celestial body and so on; then he has committed disbelief and has renounced the religion of Islam. It is advisable for you to read the chapters concerning the injunctions pertaining Riddah (renouncing the faith) in the books of Islamic Fiqh. The jurists, may Allah have mercy on them, devoted themselves to explain it. Through that, you will be able to know the previous examples on the verbal, actional, and belief-related forms of Riddah as well as the scenario concerning the renouncement of faith due to doubt.” [85] See: Fataawaa of the Permanent Committee – 1, (2/8).

16. Bakr ibn Abdullah Aboo Zayd (d. 1429 AH) states, “There are requisites and causes for deciding on Riddah and disbelief, they are the nullifiers of faith (Imaan) and Islam; from amongst the beliefs, statements, actions, doubts, or abandonment; concerning whose nullification a clear proof and glistening evidence from the Book, the Sunnah or the Ijmaa’ (consensus).” [86] Dar’ al-Fitnah ‘an Ahl as-Sunnah, p.20.