Overall meaning : This surah opens with the ‘disconnected letters’ which have already been discussed at the beginning of Surat Al-Baqarah.
This Qur’an, Allah declares, is without a doubt a revelation sent down from the Lord of all the worlds. Then, addressing His Prophet, may Allah bless him and grant him peace, He says: Do they say, ‘Muhammad has invented this Qur’an himself?!’ No indeed! It is the truth revealed to you from your Lord, so that you may warn with it a people to whom no messenger came to warn them before you, so that they may know the truth and be rightly guided!
The one and only true God who alone is worthy of worship is Allah, who created the heavens and the earth and all that lies between them in six days and established Himself upon the Throne, as befits His glory and sublime majesty. Besides Him, you have no guardian to take care of you and conduct your affairs, nor an intercessor to intercede for you with Him. Will you not, then, reflect and pay heed?!
Allah manages the affairs of His creation, and so His decree descends from the heavens to the earth, then everything that has been determined and planned, with its results and consequences, will ascend to Him on a day the length of which is a thousand years by your counting in this world.