"Verily, We have sent down to you (O Muhammad) the Book (this Quran) for mankind in truth. So whosoever accepts the guidance, it is only for his ownself; and whosoever goes astray, he goes astray only for his (own) loss. And you (O Muhammad) are not a Wakeel (trustee or disposer of affairs, or guardian) over them"
[Al-Zumar 39:4]

" And indeed, We have bestowed upon you seven of al-Mathaani (the seven repeatedly recited verses, i.e. Soorat al-Faatihah) and the Grand Quran. "
[Al-Hijr 15:87]

"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]

"And We send down from the Quran that which is a healing and a mercy to those who believe, and it increases the zaalimoon (wrongdoers) nothing but loss."
[Al-Israa 17:82]

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]