Yahya bin Ja'dah (may Allah have mercy on him) says: When the Messenger of Allah (peace and blessings be upon him) came to Madinah, he (peace and blessings be upon him) allotted houses to the people. A clan of Banu Zuhrah called Banu Abd bin Zuhrah said to him: Keep the son of Umm Abd away from us. He (peace and blessings be upon him) said: "Then for what has Allah sent me? Allah Almighty does not purify a nation until the right of the weak is taken from others and delivered to them."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب إحياء الموات / 11801