Sunan an-Nasai Book 44, Hadith 4534

أَخْبَرَنَا قُتَيْبَةُ، عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، رضى الله عنهما أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى عَنِ الْمُزَابَنَةِ وَالْمُزَابَنَةُ بَيْعُ الثَّمَرِ بِالتَّمْرِ كَيْلاً وَبَيْعُ الْكَرْمِ بِالزَّبِيبِ كَيْلاً ‏.‏

It was narrated from Ibn 'Umar that:the messenger of Allah forbade Muzabana, and Muzabanah means selling fresh dates still on tree for dried dates by measure, and selling fresh grapes for raisins by measure