Sahih al-Bukhari, Hadith 2163 ⓘ
Narrated Tawus: I asked Ibn `Abbas, "What is the meaning of, 'No town dweller should sell (or buy) for a desert dweller'?" Ibn `Abbas said, "It means he should not become his broker."
حَدَّثَنِي عَيَّاشُ بْنُ الْوَلِيدِ، حَدَّثَنَا عَبْدُ الأَعْلَى، حَدَّثَنَا مَعْمَرٌ، عَنِ ابْنِ طَاوُسٍ، عَنْ أَبِيهِ، قَالَ سَأَلْتُ ابْنَ عَبَّاسٍ ـ رضى الله عنهما ـ مَا مَعْنَى قَوْلِهِ " لاَ يَبِيعَنَّ حَاضِرٌ لِبَادٍ " . فَقَالَ لاَ يَكُنْ لَهُ سِمْسَارًا.
also referenced under: Book 34, Hadith 114 (In-Book) & Volume 3, Book 34, Hadith 372 (USC-MSA)