Quran 5:118 from Surah Al-Maaida on Divine Marvels.
إِن تُعَذِّبۡهُمۡ فَإِنَّهُمۡ عِبَادُكَۖ وَإِن تَغۡفِرۡ لَهُمۡ فَإِنَّكَ أَنتَ ٱلۡعَزِيزُ ٱلۡحَكِيمُ
English translation: If You punish them then indeed they (are) Your slaves and if You forgive [for] them then indeed You You (are) the All-Mighty the All-Wise
Transliteration: in tu'adhib'hum fa-innahum ibaduka wa-in taghfir lahum fa-innaka anta al-'azizu al-hakimu