Sahih Muslim , Book 10, Hadith 3632 (USC-MSA) ⓘ
Anas b. Malik (Allah be pleased with him) reported: We were forbidden that a townsman should sell for a man of the desert, even if he is his brother or father.
وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى، أَخْبَرَنَا هُشَيْمٌ، عَنْ يُونُسَ، عَنِ ابْنِ سِيرِينَ، عَنْ أَنَسِ، بْنِ مَالِكٍ قَالَ نُهِينَا أَنْ يَبِيعَ، حَاضِرٌ لِبَادٍ . وَإِنْ كَانَ أَخَاهُ أَوْ أَبَاهُ .
also referenced under: Book 21, Hadith 28 (In-Book) & Hadith 1523 (Reference)