On the authority of Abu Hurayrah (may Allah be pleased with him)

A man said to the Prophet (peace and blessings of Allah be upon him), “Counsel me,” so he (peace and blessings of Allah be upon him) said, “Do not become angry.” The man repeated [his request for counsel] several times, and [each time] he (peace and blessings of Allah be upon him) said, “Do not become angry.” [Al-Bukhari]