﴿ أُذِنَ لِلَّذِينَ يُقَٰتَلُونَ بِأَنَّهُمْ ظُلِمُوا۟ ۚ وَإِنَّ ٱللَّهَ عَلَىٰ نَصْرِهِمْ لَقَدِيرٌ ﴾

“PERMISSION [to fight] is given to those against whom war is being wrongfully waged and, verily, God has indeed the power to succour them -:”

Please check ayah 22:40 for complete tafsir.