لَيْسَ الشَّدِيدُ بِالصُّرَعَةِ، إِنَّمَا الشَّدِيدُ الَّذِي يَمْلِكُ نَفْسَهُ عِنْدَ الْغَضَبِ
The strong person is not merely the one who overcomes others in wrestling; true strength is controlling oneself when angry.
Source: البخاري ومسلم
لَيْسَ is an incomplete verb of negation; الشَّدِيدُ is its noun, and بِالصُّرَعَةِ supplies its predicate meaning. The prefixed بِـ strengthens the negation. إِنَّمَا emphasizes the real criterion, while يَمْلِكُ نَفْسَهُ means controlling oneself.
Overpowering another person can display physical skill, but refraining from abuse, violence, or rash reactions when provoked requires moral strength. The narration does not deny physical ability; it places self-mastery at the heart of genuine strength.