Sahih al-Bukhari 2171
Sahih al-Bukhari · Book 34: Sales and Trade · The selling of dried grapes for dried grapes and meals for meals
Narrated Ibn `Umar:
حَدَّثَنَا إِسْمَاعِيلُ ، حَدَّثَنَا مَالِكٌ ، عَنْ نَافِعٍ ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ ـ رضى الله عنهما ـ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى عَنِ الْمُزَابَنَةِ، وَالْمُزَابَنَةُ بَيْعُ الثَّمَرِ بِالتَّمْرِ كَيْلاً، وَبَيْعُ الزَّبِيبِ بِالْكَرْمِ كَيْلاً.
Allah's Messenger (ﷺ) forbade Muzabana; and Muzabana is the selling of fresh dates for dried old dates by measure, and the selling of fresh grapes for dried grapes by measure.