Surah 17. Al-Israa, Ayah 106

Lit., "which We have divided into [consecutive] parts" or, according to some authorities (quoted by Razi), "set forth with clarity". The rendering adopted by me allows for both these meanings.

The above verse alludes both to the historical fact that the process of the revelation of the Qur'an was gradual, extending over the twenty-three years of the Prophet's ministry, and to the fact that it is nevertheless one integral whole and can, therefore, be properly understood only if it is considered in its entirety - that is to say, if each of its passages is read in the light of all the other passages which it contains. (See also 20:114 and the corresponding note [101].)

The marvel is that these parts, revealed at different times and in different circumstances, should fit together so closely and consistently as they do. All revelation is progressive. The previous revelations were also progressive. Each of them marked a stage in the world's spiritual history. Man's mind does not take in more than his spiritual state will have prepared him, for Allah's revelation comes as a light to illuminate our difficulties and show us the way in actual situations that arise.