Quran 32:12 from Surah As-Sajda on Divine Marvels.
وَلَوۡ تَرَىٰٓ إِذِ ٱلۡمُجۡرِمُونَ نَاكِسُواْ رُءُوسِهِمۡ عِندَ رَبِّهِمۡ رَبَّنَآ أَبۡصَرۡنَا وَسَمِعۡنَا فَٱرۡجِعۡنَا نَعۡمَلۡ صَٰلِحًا إِنَّا مُوقِنُونَ
English translation: And if you (could) see when the criminals (will) hang their heads before their Lord Our Lord we have seen and we have heard so return us we will do righteous (deeds) Indeed we (are now) certain
Transliteration: walaw tara idhi al-muj'rimuna nakisu ruusihim inda rabbihim rabbana absarna wasami'na fa-ir'ji'na na'mal salihan inna muqinuna