Riyad as-Salihin 1777
Ibn 'Abbas (May Allah be pleased with them) said:
The Messenger of Allah (ﷺ) said, "The caravans carrying merchandise should not be met on the way to purchase from them; a man in the city should not sell for a man of the desert." Tawus asked him (Ibn 'Abbas): "What do these words really imply?" He said: "He should not work as an agent on his behalf." [Al-Bukhari and Muslim] .
وعن ابن عباس رضي الله عنهما قال‏:‏ قال رسول الله صلى الله عليه وسلم ‏:‏ “لا تتلقوا الركبان، ولا يبع حاضر لباد‏"‏ فقال له طاوس‏:‏ ما قوله‏:‏ لا بيع حاضر لباد‏؟‏ قال‏:‏ لا يكون له سمسارًا‏.‏ ‏(‏‏(‏متفق عليه‏)‏‏)‏‏.‏