Sahih al-Bukhari
Sahih al-Bukhari 2139
Arabic hadith text
حَدَّثَنَا إِسْمَاعِيلُ، قَالَ حَدَّثَنِي مَالِكٌ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ ـ رضى الله عنهما ـ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " لاَ يَبِيعُ بَعْضُكُمْ عَلَى بَيْعِ أَخِيهِ ".
Translation
Ismail narrated to us; he said: Malik narrated to me, from Nafi, from Abdullah ibn Umar, may Allah be pleased with them both, that the Messenger of Allah said: “None of you should undercut his brother in a sale.”