Messenger of Allah ﷺ said, "Help your brother, whether he is an oppressor or he is an oppressed one. People asked, "O Messenger of Allah ﷺ! It is all right to help him if he is oppressed, but how should we help him if he is an oppressor?" The Prophet ﷺ said, "By preventing him from oppressing others."
قَالَ رَسُولُ اللَّهِ ﷺ انْصُرْ أَخَاكَ ظَالِمًا أَوْ مَظْلُومًا قَالُوا يَا رَسُولَ اللَّهِ هَذَا نَنْصُرُهُ مَظْلُومًا فَكَيْفَ نَنْصُرُهُ ظَالِمًا قَالَ تَأْخُذُ فَوْقَ يَدَيْهِ