Sahih Muslim
The Book of Transactions (Kitab Al-Buyu)
Book Number: 010 / Hadith Number: 3691
Sahl b. Abu Hathma reported Allah's Messenger (may peace be upon him) having forbidden Muzabana, i. e. exchange of fresh dates with dry dates. except in case of those to whom donations of some trees have been made. It is for them that concession has been given.