Ibn Abbas reported that the Messenger of Allah ﷺ forbade going out to meet the caravans before they reached the market, and forbade a town-dweller from selling on behalf of a desert-dweller.The narrator said, I asked Ibn Abbas, "What does his statement 'a town-dweller selling for a desert-dweller' mean?"He replied, "He should not act as a broker for him."
عن ابن عباس قال: نهي رسول الله ﷺ أن تتلقى الركبان، وأن يبيع حاضر لباد. قال: فقلت لابن عباس: ما قوله حاضر لباد؟ قال: لا يكن له سمسارا.
Bukhari narrated it in "Sales" (2158), and Muslim narrated it in "Sales" (1521), both of them through the route of Mamar, from Abdullah bin Tawus, from his father, from Ibn Abbas, who mentioned it.