Qur'an 22:39

أُذِنَ لِلَّذِينَ يُقَـٰتَلُونَ بِأَنَّهُمْ ظُلِمُوا۟ ۚ وَإِنَّ ٱللَّهَ عَلَىٰ نَصْرِهِمْ لَقَدِيرٌ

“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.”

Al-Hajj 22:39 · Saheeh International