Surah Al-Hajj, Verse 39

أُذِنَ لِلَّذِينَ يُقَٰتَلُونَ بِأَنَّهُمۡ ظُلِمُواْۚ وَإِنَّ ٱللَّهَ عَلَىٰ نَصۡرِهِمۡ لَقَدِيرٌ٣٩

udhina lilladhīna yuqātalūna bi-annahum ẓulimū wa-inna l-laha ʿalā naṣrihim laqadīrun

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.