Musnad Ahmad 1018:110

'Abd al-Razzaq narrated to us, Ma'mar informed us, from al-Zuhri, from Humayd ibn 'Abd al-Rahman, from a man among the companions of the Prophet, may God bless him and grant him peace, who said: A man said: "O Messenger of God, advise me." He said: "Do not become angry." The man said: So I reflected when the Prophet, may God bless him and grant him peace, said what he said, and behold, anger gathers all evil.