Sura al-Ḥajj 22:60

ذَٰلِكَ وَمَنْ عَاقَبَ بِمِثْلِ مَا عُوقِبَ بِهِۦ ثُمَّ بُغِىَ عَلَيْهِ لَيَنصُرَنَّهُ ٱللَّـهُ إِنَّ ٱللَّـهَ لَعَفُوٌّ غَفُورٌ

dhālika wa-man ʿāqaba bi-mithli mā ʿūqiba bihi thumma bughiya ʿalayhi la-yanṣurannahu allāhu inna allāha laʿafūwun ghafūrun

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).