Aswad bin Asram reported,

Aswad reported that he once brought some of his fat camels to Madinah during a time of drought and barrenness in the land. When the people of Madinah saw them, they marveled at how plump they were, and the matter was mentioned to the Messenger.The Messenger of Allah ﷺ sent for the camels, and they were brought to him. He came out, looked at them, and asked, "Why have you brought these camels of yours to display them?"Aswad replied, "I want to exchange them for a servant."The Messenger of Allah ﷺ asked, "Who has a servant to offer?"Uthman bin Affan said, "I do, Messenger of Allah."The Prophet said, "Bring the servant."Uthman brought the servant, and when Aswad saw him, he said, "This is exactly the kind I want."Uthman said, "He is yours, take him."So Aswad took the servant, and the Messenger of Allah ﷺ took possession of his camels.Then Aswad said, "Messenger of Allah, give me some advice."The Prophet asked, "Do you have control over your tongue?"Aswad replied, "What do I control if I do not control that?"The Prophet asked, "Do you have control over your hand?"Aswad replied, "What do I control if I do not control my hand?"The Prophet said, "Then say nothing with your tongue except what is good, and do not extend your hand except toward what is good."

عن أسود بن أصرم المحاربي

أنه قدم بإبل له سمان إلى المدينة في زمن قحل وجدوب من الأرض، فلما رآها أهل المدينة عجبوا من سمنها، فذكرت ذلك للرسول، فأرسل إليها رسول الله ﷺ فأتي بها، فخرج إليها، فنظر إليها، فقال: لم جليت إبلك هذه؟ قال: أردت بها خادما، فقال رسول الله ﷺ: من عنده خادم؟ فقال عثمان ابن عفان: عندي يا رسول الله، قال: فاتت بها، فجاء بها عثمان، فلما رآها أسود، قال: مثلها أريد، فقال: عندك فخذها، فأخذها أسود، وقبض رسول الله ﷺ إبله، فقال أسود: يا رسول الله، أوصني، قال: هل تملك لسانك؟ قال: فما أملك إذا لم أملكه؟ قال: أفتملك يدك؟ قال: فماذا أملك إذا لم أملك يدي؟ قال: فلا تقل بلسانك إلا معروفا، ولا تبسط يدك إلا إلى خير.