Hadith 1163
Sayyiduna Anas bin Malik (may Allah be pleased with him) reports that the Messenger of Allah (peace and blessings be upon him) said: "Help your brother, whether he is an oppressor or oppressed." I said: O Messenger of Allah! I will help the oppressed, but how can I help the oppressor? The Prophet (peace and blessings be upon him) said: "You stop him from oppression; that is your help to him."