Surah As-Sajdah, verse 1

تَنزِيلُ ٱلْكِتَـٰبِ لَا رَيْبَ فِيهِ مِن رَّبِّ ٱلْعَـٰلَمِينَ ﴿٢﴾

[This is] the revelation of the Book about which there is no doubt from the Lord of the worlds.

أَمْ يَقُولُونَ ٱفْتَرَىٰهُ ۚ بَلْ هُوَ ٱلْحَقُّ مِن رَّبِّكَ لِتُنذِرَ قَوْمًۭا مَّآ أَتَىٰهُم مِّن نَّذِيرٍۢ مِّن قَبْلِكَ لَعَلَّهُمْ يَهْتَدُونَ ﴿٣﴾

Or do they say, "He invented it"? Rather, it is the truth from your Lord, [O Muḥammad], that you may warn a people to whom no warner has come before you [so] perhaps they will be guided.