Hadith 16, 40 Hadith an-Nawawi
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]
عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللهُ عَنْهُ أَنَّ رَجُلًا قَالَ لِلنَّبِيِّ صلى الله عليه و سلم أَوْصِنِي. قَالَ: لَا تَغْضَبْ، فَرَدَّدَ مِرَارًا، قَالَ: لَا تَغْضَبْ" .   
[رَوَاهُ الْبُخَارِيُّ].