Sahih al-Bukhari 2139

Arabic

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 ‏"‏‏.‏

English translation

Narrated `Abdullah bin `Umar:Allah's Messenger (ﷺ) said, "Do not urge somebody to return what he has already bought (i.e. in optional sale) from another seller so as to sell him your own goods

Reference: Sahih al-Bukhari 2139, Book of Sales and Trade. English translation by Dr. Muhammad Muhsin Khan.