Bulugh al-Maram, Book 16, Hadith 1535 (English)

Abu Hurairah (RAA) narrated, ‘A man said, “O Messenger of Allah, advise me.” The Messenger of Allah said: “Do not get angry.” The man repeated that several times and he replied, “Do not get angry.” Related by Al-Bukhari.

وَعَنْهُ أَنَّ رَجُلاً قَالَ: { يَا رَسُولَ اَللَّهِ! أَوْصِنِي.‏ فَقَالَ: لَا تَغْضَبْ, فَرَدَّدَ مِرَارًا.‏ قَالَ: لَا تَغْضَبْ } أَخْرَجَهُ اَلْبُخَارِيُّ.‏ (1954)‏.‏ ‏1 ‏- صحيح.‏ رواه البخاري (6116)‏.‏

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also referenced under: Book 16, Hadith 1492 (In-Book)