Surah Al-Hajj (The Pilgrimage), Verse 60

ذٰلِكَ وَمَنْ عَاقَبَ بِمِثْلِ مَا عُوْقِبَ بِهٖ ثُمَّ بُغِیَ عَلَیْهِ لَیَنْصُرَنَّهُ اللّٰهُ اِنَّ اللّٰهَ لَعَفُوٌّ غَفُوْرٌ ۟

Zaalika wa man 'aaqaba bimisli maa 'ooqiba bihee summa bughiya 'alaihi la yansurannahul laah; innal laaha la 'Afuwwun Ghafoor

“That (is so). And if one has retaliated to no greater extent than the injury he received, and is again set upon inordinately, Allah will help him: for Allah is One that blots out (sins) and forgives (again and again).”

Quran 22:60 (Yusuf Ali Translation)