سنن النسائي

It was narrated that Qays bin Abi Gharazah said: "We used to trade in the markets of Al-Madinah and we used to call ourselves as-Samasir (brokers) and the people called us that, but the Messenger of Allah (ﷺ) came out to s and called us by a name that was better than what we called ourselves. He said: "O merchants (Tujjar)! Selling involves (false) oaths and idle talk, so mix some charity with it,"" (Sahih )