Surah Az-Zumar, Verse 56

أَن تَقُولَ نَفۡسٞ يَٰحَسۡرَتَىٰ عَلَىٰ مَا فَرَّطتُ فِي جَنۢبِ ٱللَّهِ وَإِن كُنتُ لَمِنَ ٱلسَّٰخِرِينَ٥٦

an taqūla nafsun yāḥasratā ʿalā mā farraṭtu fī janbi l-lahi wa-in kuntu lamina l-sākhirīna

Lest a soul should say, "Oh, [how great is] my regret over what I neglected in regard to Allāh and that I was among the mockers."