The definition of imprecation (li’aan): The linguistic meaning of the Arabic word Li’aan (imprecation) is cursing, and its relevance to imprecation is because the husband asks Allah in the last statement to bestow His curse upon him had he been lying about it, and the meaning of curse is expulsion and deportation. However, the term in Islam refers to the four oath-based testimonies of the husband against his wife, which he concludes with asking Allah to bestow His curse upon him if he was lying, and the four oath-based testimonies of the wife to deny the accusations of her husband,  which she concluded that Allah’s anger is upon her if her husband was telling the truth. The part of the husband removes the punishment for accusing a woman of committing adultery without being able to produce four credible witnesses, and the part of the wife saves her from being liable for the punishment of adultery.
2. The wording of imprecation (li’aan): The scholars are in consensus that the wordings of imprecation are as follows: The husband will have to take the oath four times that his wife is adulterous, and he is being truthful in accusing his wife. In the fifth oath,  the husband will have to invoke the Curse of Allah upon him in case he is lying. The wife, in return, will have to take the oath four times that her husband is telling a lie and in the fifth oath to say that may the Wrath of Allah be upon her if he is telling the truth concerning her. This agreement of scholars is reported by Ibn Hazm and Ibn al-Qattaan.
3. The ruling of imprecation: The scholars are in consensus that imprecation (li’aan) is permissible. This consensus is reported by al-Maawardee, Ibn Rushd – the grandfather, Ibn Rushd - the Grandson, and Ibn Hajar.