Al-Hijr 15:9

It is We Who have sent down the Reminder[5], and it is We Who will preserve it[6].

[5] As a reminder for people.
[6] From distortion, alteration, addition, and omission. More than 1400 years have elapsed and not a single word of this Qur’an has been changed, although enemies have tried their utmost.

Indeed, it is We who sent down the message [i.e., the Qur’ān], and indeed, We will be its guardian.

9. Verily, We, it is We Who have sent down the Dhikr (i.e. the Qur’ân) and surely, We will guard it (from corruption)[2].

[2] (V.15:9) This Verse is a challenge to mankind and everyone is obliged to believe in the miracles of this Qur’ân. It is a clear fact that more than 1400 years have elapsed and not a single word of this Qur’ân has been changed, although the disbelievers tried their utmost to change it in every way, but they failed miserably in their efforts. As it is mentioned in this holy Verse: "We will guard it." By Allâh! He has guarded it. On the contrary, all the other holy Books [the Taurât (Torah), the Injeel (Gospel).] have been corrupted in the form of additions or subtractions or alterations in the original text.

Lo! We, even We, reveal the Reminder, and lo! We verily are its Guardian.