Preservation of Revelation

وَإِن كَادُوا۟ لَيَفْتِنُونَكَ عَنِ ٱلَّذِىٓ أَوْحَيْنَآ إِلَيْكَ لِتَفْتَرِىَ عَلَيْنَا غَيْرَهُۥ ۖ وَإِذًا لَّٱتَّخَذُوكَ خَلِيلًا

And indeed, they were about to tempt you away from that which We revealed to you in order to [make] you invent about Us something else; and then they would have taken you as a friend.

وَإِنَّهُۥ لَقَسَمٌ لَّوْ تَعْلَمُونَ عَظِيمٌ

And indeed, it is an oath - if you could know - [most] great.