Quran Al-Hajj 22:39
أُذِنَ لِلَّذِينَ يُقَٰتَلُونَ بِأَنَّهُمۡ ظُلِمُواْۚ وَإِنَّ ٱللَّهَ عَلَىٰ نَصۡرِهِمۡ لَقَدِيرٌ ٣٩
Translation
Permission [to fight] has been given to those who are being fought, because they were wronged. And indeed, Allāh is competent to give them victory.