Sayyiduna Abdullah bin Umar (may Allah be pleased with them) narrates that the Prophet Muhammad (peace and blessings be upon him) said: "Help your brother whether he is an oppressor or oppressed." It was asked, "O Messenger of Allah (peace be upon him)! Helping the oppressed is understandable, but how can I help the oppressor?" The Prophet Muhammad (peace and blessings be upon him) said: "Stop him from committing oppression; that is your helping him."
Hadith Referenceصحیح ابن حبان / كتاب الغصب / 5166
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح لغيره - «الإرواء» (8/ 97).فضيلة الشيخ العلّامة شُعيب الأرناؤوطNull