Quran 6:27 from Surah Al-An'aam on Divine Marvels.
وَلَوۡ تَرَىٰٓ إِذۡ وُقِفُواْ عَلَى ٱلنَّارِ فَقَالُواْ يَٰلَيۡتَنَا نُرَدُّ وَلَا نُكَذِّبَ بِـَٔايَٰتِ رَبِّنَا وَنَكُونَ مِنَ ٱلۡمُؤۡمِنِينَ
English translation: And if you (could) see when they are made to stand by the Fire then they (will) say Oh! Would that we were sent back and not we would deny (the) Signs (of) our Lord and we would be among the believers
Transliteration: walaw tara idh wuqifu ala al-nari faqalu yalaytana nuraddu wala nukadhiba biayati rabbina wanakuna mina al-mu'minina