If You should punish them - indeed they are Your servants; but if You forgive them - indeed it is You who is the Exalted in Might, the Wise.
The Saheeh International Quran Translation
إِن تُعَذِّبْهُمْ فَإِنَّهُمْ عِبَادُكَ وَإِن تَغْفِرْ لَهُمْ فَإِنَّكَ أَنتَ ٱلْعَزِيزُ ٱلْحَكِيمُIf You should punish them - indeed they are Your servants; but if You forgive them - indeed it is You who is the Exalted in Might, the Wise.