It was narrated that Qais bin Abi Gharazah said: "At the time of the Messenger of Allah (ﷺ) we used to be called Samasir (brokers). The Messenger of Allah (ﷺ) came to us when we were selling and called us by a name that was better than that. He said: 'O merchants (Tujjar), this selling involves lies and (false) oaths, so mix some charity with it.'"
Source: sunnah.com
Other translations
Arabic
أَخْبَرَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدِ بْنِ عَبْدِ الرَّحْمَنِ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ عَبْدِ الْمَلِكِ، عَنْ أَبِي وَائِلٍ، عَنْ قَيْسِ بْنِ أَبِي غَرَزَةَ، قَالَ كُنَّا نُسَمَّى السَّمَاسِرَةَ فَأَتَانَا رَسُولُ اللَّهِ صلى الله عليه وسلم وَنَحْنُ نَبِيعُ فَسَمَّانَا بِاسْمٍ هُوَ خَيْرٌ مِنِ اسْمِنَا فَقَالَ " يَا مَعْشَرَ التُّجَّارِ إِنَّ هَذَا الْبَيْعَ يَحْضُرُهُ الْحَلِفُ وَالْكَذِبُ فَشُوبُوا بَيْعَكُمْ بِالصَّدَقَةِ " .
sunnah.com