Quran 29:48 Al-'Ankabut, ayah 48 of 69

وَمَا كُنتَ تَتْلُوا۟ مِن قَبْلِهِۦ مِن كِتَـٰبٍ وَلَا تَخُطُّهُۥ بِيَمِينِكَ ۖ إِذًا لَّٱرْتَابَ ٱلْمُبْطِلُونَ ۝٤٨

29:48 And thou (O Muhammad) wast not a reader of any scripture before it, nor didst thou write it with thy right hand, for then might those have doubted, who follow falsehood.