Reported by Anas (RA): Allah's Messenger (peace be upon him) said, 'Help your brother, whether he is an oppressor or he is an oppressed one. People asked, 'O Allah's Messenger! It is all right to help him if he is oppressed, but how should we help him if he is an oppressor?' The Prophet (peace be upon him) said, 'By preventing him from oppressing others.' [Bukhari]