Sahih Muslim Book 10, Hadith Number 3699.

Chapter : It is forbidden to sell fresh dates against dry dates, except in case of al-Araya.

Abdullah (b. Umar) (Allah be pleased with them) reported Allah’s Messenger (may peace be upon him) having forbidden Mazabana, and it implies that one should sell the fresh fruits of his orchard (for dry fruits) or, if it is fresh dates, for dry dates with a measure, or if it is grapes for raisins or if it is corn in the field for dry corn with a measure He (the Holy Prophet) in fact forbade all such transactions. Qutaiba has narrated it with a slight variation of words. This hadith has been narrated on the authority of Nafi with another chain of transmitters.