(6) باب تَحْرِيمِ بَيْعِ الْحَاضِرِ لِلْبَادِي
Abu Huraira (Allah be pleased with him) reported it directly from Allah's Apostle (ﷺ):
The townsman'should not sell for a man from the desert (with a view to taking advantage of his ignorance of the market conditions of the city). And Zuhair reported from the Prophet (ﷺ) that he forbade the townsman to sell on behalf of the man from the desert.
Reference: Sahih Muslim 1520
In-book reference: Book 21, Hadith 24
USC-MSA web (English) reference(deprecated numbering scheme): Book 10, Hadith 3628