“We have revealed the Qur'an in parts that you may recite it to people slowly and with deliberation; and (for that reason) We have revealed it gradually [to suit particular occasions]. Tell them, (O Prophet!): ‘Believe in it, or do not believe’; when it is recited to those who were given the knowledge before its revelation, they fall down upon their faces in prostration, and say: ‘Glory be to our Lord. Surely the promise of our Lord was bound to be fulfilled.’ And they fall down upon their faces, weeping, and their humility increases when they hear recitation of the Quran.
( Qur'an – 17:107-109)
These verses were in response to the detractors’ charge as to why God’s Message was not revealed in one piece, why it was delivered, instead, at intervals. That the Qur'an was revealed gradually rather than in one piece does not prove any deficiency in God’s knowledge or wisdom. It is rather man’s power of comprehension and assimilation which is deficient. Hence, if the Qur'an had been revealed in one piece, it would have been difficult for people to assimilate its whole message in a short span of time. Nor would it have been easy to fully digest even a single aspect of that message in a limited period of time. Thus God, in His wisdom, entrusted Gabriel to communicate the Qur'an to the Messenger (may Allah bless and greet him) in pieces. At times, the Quranic messages were set out succinctly and at other times in some detail. The literary style employed to explain the messages also varied. One and the same point is driven home by variously employing different methods. All this is done so that all those who seek the truth might be able to obtain it despite their varying intellectual endowments, and subsequently grow mature in their knowledge, conviction and understanding. The believers who follow the way of God encounter many problems in due course. The Qur'an provides them with timely guidance. It would have been altogether unwise to reveal directives in connection with all the different problems before people even encountered them.