Tawus from Ibn 'Abbas (RA), Allah's Messenger (ﷺ) said:
"Do not go out to meet riders (to conduct business with them), and a city-dweller must not sell for a man from the desert." I asked Ibn 'Abbas (RA), "What did he mean by 'A city-dweller must not sell for a man from the desert.'" He replied, "He should not act as a broker for him."
[Agreed upon and the wording is al-Bukhari's].