Ultimate authority of Allah's words

وَٱتْلُ مَآ أُوحِىَ إِلَيْكَ مِن كِتَابِ رَبِّكَ ۖ لَا مُبَدِّلَ لِكَلِمَـٰتِهِۦ وَلَن تَجِدَ مِن دُونِهِۦ مُلْتَحَدًا

And recite, [O Muḥammad], what has been revealed to you of the Book of your Lord. There is no changer of His words, and never will you find in other than Him a refuge.