"Verily, We, it is We Who have sent down the Dhikr (i.e. the Quran) and surely, We will guard it (from corruption)"
[Al-Hijr 15:9]

"Then High above all be Allah, the True King. And be not in haste (O Muhammad) with the Quran before its revelation is completed to you, and say: "My Lord! Increase me in knowledge."
[Ta-Ha 20:114]

"And (it is) a Quran which We have divided (into parts), in order that you might recite it to men at intervals. And We have revealed it by stages."
[Al-Israa 17:106]

Alif Laam Raa. A book which we have revealed to you (Muhammad) so that you may lead the people from out of the darknesses into the light by their Lord's leave, to the path of the Almighty, the Praiseworthy.
[Ibrahim 14:1]

"And indeed, We have made the Quran easy to understand and remember, then is there any that will remember (or receive admonition)?"
[Al-Qamar 54:40]