Quran 42, Ash-Shura (Counsel)

42:41And whoso defendeth himself after he hath suffered wrong - for such, there is no way (of blame) against them.

وَلَمَنِ انْتَصَرَ بَعْدَ ظُلْمِهِ فَأُولَئِكَ مَا عَلَيْهِمْ مِنْ سَبِيلٍ