And those who do not believe say, “”Why has not the whole Quran been sent down on him all at once?”” Thus (We have not sent it down all at once) that We may make your heart firm through it, and (therefore) We have caused the Quran to be recited to you gradually (in portions, after) intervals {1}.
“Had We sent down this Quran on a mountain you would have seen it fallen down splitting asunder due to the fear of Allah”. (Chapter: 59 Verse 21)
It is reported that when portions of the Quran were sent down on the messenger of Allah while on the camel back, the camel used to sit down due to the load. the messenger of Allah himself used to perspire. (Seerat -un-Nabi by Syed Sulaiman Nadvi, 1928, Vol 3. P. 302-303). It was probably due to this reason that the whole Quran was not communicated all at once. It would probably not be possible for a human heart to bear the pressure which could crush a mountain. The first portion of the Quran consisted of only five verses (96; 1-5), then the second installment (Chapter: 74) was communicated after a long interval, the whole Quran being communicated in small portions, in a span of twenty-three years, probably to dissipate the tremendous pressure inherent in it.
