An-Nahl 16:126

وَإِنۡ عَاقَبۡتُمۡ فَعَاقِبُواْ بِمِثۡلِ مَا عُوقِبۡتُم بِهِۦۖ وَلَئِن صَبَرۡتُمۡ لَهُوَ خَيۡرٞ لِّلصَّـٰبِرِينَ 126

And if you punish [an enemy, O believers], punish with an equivalent of that with which you were harmed. But if you are patient - it is better for those who are patient