With the succor of God...
(15:9) The late `Allamah Tabatabai says in regard to this verse: It (the Qur'an) is the everlasting Remembrance, secure from being lost or forgotten. It is secure from any addition or decrease which may deprive it from being the Remembrance. It is secure from any change in its form and text that may alter its quality of being a Divine Reminder expounding the truths of the Divine teaching. Hence this verse indicates the security of the Divine Scripture from all kinds of tahrif.
The verse, together with its context, indicates the security of the Remembrance, that is, the Qur'an, for ever after its revelation.4 Al-Zamakhshari, while discussing this verse, says: He (God) is its protector at all times from every kind of addition or loss, alteration or change, unlike the former scriptures. This is an indication that the Qur'an is a sign sent down by Him.
For had it not been a Divine sign or had it been the speech of a mortal, it would have been subject to increase and decrease, as happens in all speech other than it.5 Al-Sayyid al-Khui says: This verse signifies that the Qur'an is secure from tahrif and that it is not possible for the hands of tyrants to make a plaything of it.6 Al-Fakhr al-Razi says regarding this verse: (It means that) We shall protect this Remembrance from tahrif, addition and loss.7 Al-Fayd al-Kashani says: (It means), We shall protect it from tahrif, addition and loss.8 Abu `Ali al-Tabarsi says: `And We are its protector' means that We shall protect it from addition and loss, tahrif and change.