Sahih al-Bukhari #6116
Sahih (Authentic)
Good Manners
لَيْسَ الشَّدِيدُ بِالصُّرَعَةِ إِنَّمَا الشَّدِيدُ الَّذِي يَمْلِكُ نَفْسَهُ عِنْدَ الْغَضَبِ
The Prophet (ﷺ) said, 'The strong is not the one who overcomes the people by his strength, but the strong is the one who controls himself while in anger.'
Chain of Narration (Isnad)
Narrated Abu Huraira