Quran 6:156 from Surah Al-An'aam on Divine Marvels.
أَن تَقُولُوٓاْ إِنَّمَآ أُنزِلَ ٱلۡكِتَٰبُ عَلَىٰ طَآئِفَتَيۡنِ مِن قَبۡلِنَا وَإِن كُنَّا عَن دِرَاسَتِهِمۡ لَغَٰفِلِينَ
English translation: Lest you say Only was revealed the Book on the two groups from before us and indeed we were about their study certainly unaware
Transliteration: an taqulu innama unzila al-kitabu ala taifatayni min qablina wa-in kunna an dirasatihim laghafilina