It was narrated to us by Moḥammed bin al-Ḥassan رحمه الله, from Moḥammed bin al-Ḥassan al-Ṣaffār, who said – it was narrated to us by al-ʿAbbās bin Maʿrūf, who said – it was narrated to us by Moḥammed bin Yaḥya al-Khazāz, from Ghiyāth bin Ibrāhīm, from al-Ṣādiq, Jaʿfar bin Moḥammed, from his father, from his grandfather عليهم السلام who said:

The Messenger of Allāh صلى الله عليه وآله passed by a people who were weightlifting with a rock. He said: “What is this [that you are doing]?”
They said: “So that we come to know with this who is the toughest and strongest of us.”
He صلى الله عليه وآله said: “Shall I inform you who is the toughest and strongest of you all?”
They said: “Yes, oh Messenger of Allāh.”
He said: “The toughest and strongest of you is the one who when is pleased, his pleasure does not enter him into sin or falsehood; and when he is angry, his anger does not take him from speaking the truth; and when he is empowered, he does not seize that in which he has no right over.”

حدثنا محمد بن الحسن (رحمه الله)، قال: حدثنا محمد بن الحسن الصفار، قال: حدثنا العباس بن معروف، قال: حدثنا محمد بن يحيى الخزاز، عن غياث بن إبراهيم، عن الصادق جعفر بن محمد، عن أبيه، عن جده (عليهم السلام)، قال: مر رسول الله (صلى الله عليه وآله) بقوم يربعون حجرا، قال: ما هذا؟ قالوا: نعرف بذلك أشدنا وأقوانا. فقال (صلى الله عليه وآله): ألا أخبركم بأشدكم وأقواكم؟ قالوا: بلى، يا رسول الله. قال: أشدكم وأقواكم الذي إذا رضي لم يدخله رضاه في إثم ولا باطل، وإذا سخط لم يخرجه سخطه من قول الحق، وإذا قدر لم يتعاط ما ليس له بحق