Musnad Ahmad 30:522

'Abd al-Razzaq narrated to us, Ma'mar and 'Abd al-A'la informed us, from Ma'mar, from al-Zuhri, from Humayd ibn 'Abd al-Rahman, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The strong one is not the one who overcomes people in wrestling." They said: "Then who is the strong one, O Messenger of Allah?" He said: "The one who controls himself when he is angry."