Sahih al-Bukhari 2161
Sahih al-Bukhari · Book 34: Sales and Trade · A town dweller should not buy goods for a desert dweller and charge commission as a broker
Narrated Anas bin Malik:
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى ، حَدَّثَنَا مُعَاذٌ ، حَدَّثَنَا ابْنُ عَوْنٍ ، عَنْ مُحَمَّدٍ ، قَالَ أَنَسُ بْنُ مَالِكٍ ـ رضى الله عنه ـ نُهِينَا أَنْ يَبِيعَ حَاضِرٌ لِبَادٍ.
We were forbidden that a town dweller should sell goods of a desert dweller.