The Quran

وَإِذا تُتلىٰ عَلَيهِم آياتُنا بَيِّناتٍ ۙ قالَ الَّذينَ لا يَرجونَ لِقاءَنَا ائتِ بِقُرآنٍ غَيرِ هٰذا أَو بَدِّلهُ ۚ قُل ما يَكونُ لي أَن أُبَدِّلَهُ مِن تِلقاءِ نَفسي ۖ إِن أَتَّبِعُ إِلّا ما يوحىٰ إِلَيَّ ۖ إِنّي أَخافُ إِن عَصَيتُ رَبّي عَذابَ يَومٍ عَظيمٍ

Muhammad Asad

AND [thus it is:] whenever Our messages are conveyed unto them in all their clarity, those who do not believe that they are destined to meet Us [are wont to] say, "Bring us a discourse other than this, or alter this one.¹ Say [O Prophet]: "It is not conceivable that I should alter it of my own volition; I only follow what is revealed to me. Behold, I would dread, were I [thus] to rebel against my Sustainer, the suffering [which would befall me] on that awesome Day [of Judgment]!"

Sc., "to suit our own views as to what is right and what is wrong". This is an oblique reference to the highly subjective criticism of Qur'anic ethics and eschatology by many agnostics (both among the contemporaries of the Prophet and in later times), and particularly to their view that the Qur'an was "composed" by Muhammad himself and therefore expresses no more than his personal convictions. - Regarding the phrase, "those who do not believe that they are destined to meet Us", see note 12 above.