Musnad Ahmad 32:1584

Mu'ammal narrated to us, Hammad—meaning Ibn Salamah—narrated to us, Ali ibn Zayd narrated to us, he said: Something reached Mus'ab ibn al-Zubayr regarding the leader (arif) of the Ansar, and he intended to do something to him. Anas ibn Malik entered upon him and said to him: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "Treat the Ansar well—or he said: with kindness—accept from their doers of good, and overlook their wrongdoers." Mus'ab threw himself off his throne, pressed his cheek against the carpet, and said: The command of the Messenger of Allah, peace and blessings of Allah be upon him, is upon the head and the eyes. So he left him alone.