Muwatta Malik, Book 47, Hadith 12 (USC-MSA)

Yahya related to me from Malik from Ibn Shihab from Said ibn al- Musayyab from Abu Hurayra that the Messenger of Allah, may Allah bless him and grant him peace, said, "A strong person is not the person who throws his adversaries to the ground. A strong person is the person who contains himself when he is angry."

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏ "‏ لَيْسَ الشَّدِيدُ بِالصُّرَعَةِ إِنَّمَا الشَّدِيدُ الَّذِي يَمْلِكُ نَفْسَهُ عِنْدَ الْغَضَبِ ‏" ‏ ‏.‏

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also referenced under: Book 47, Hadith 1647 (In-Book)