أَفَلَا يَتَدَبَّرُونَ ٱلْقُرْءَانَ ۚ وَلَوْ كَانَ مِنْ عِندِ غَيْرِ ٱللَّهِ لَوَجَدُوا۟ فِيهِ ٱخْتِلَـٰفًا كَثِيرًا
Do they not contemplate the Quran? Had it been from [someone] other than Allah, they would have surely found much discrepancy in it.