I saw Abu Hurairah when we were boys. The Bedouins would come, and one of us would say, "Arabi, we will sell your goods for you."Abu Hurairah said, "Leave him alone, let him sell his own merchandise."Then Abu Hurairah said, "The Messenger of Allah ﷺ forbade a town-dweller from selling on behalf of a desert-dweller."
حدثنا ربعي بن إبراهيم حدثنا عبد الرحمن بن إسحاق
رأيت أبا هريرة ونحن غلمان تجيء الأعراب يقول يا أعرابي نحن نبيع لك قال دعوه فليبع سلعته فقال أبو هريرة إن رسول الله ﷺ نهى أن يبيع حاضر لباد
Its isnad is sahih. Muslim bin Abu Muslim al-Khayyat al-Makki, we already established his reliability at 5010, and we add here that Ibn Abu Hatim also mentioned him in his biographical work, 4/1/196. The hadith is lengthy at 7310, where the part attributed to the Prophet already appeared, with the same meaning, but without the story that comes at the beginning here.