Bismillah Walhamdulillah Was Salaatu Was Salaam ‘ala Rasulillah Narrated Anas (Radi-Allahu ‘anhu):

Allah’s Apostle (Sallallahu ‘Alaihi Wa Sallam) said, “Help your brother, whether he is an oppressor or he is an oppressed one. People asked, “O Allah’s Apostle! It is all right to help him if he is oppressed, but how should we help him if he is an oppressor?” The Prophet (Sallallahu ‘Alaihi Wa Sallam) said, “By preventing him from oppressing others.”

Bukhari Vol. 3 : No. 624