Sahih Muslim Book 10, Hadith Number 3688.

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

Bushair b. Yasar reported on the authority of some of the Companion of Allah’s Messenger (may peace be upon him) that he exempted the transactions, of ‘ariyya (from the direct exchange of one kind) after measuring the dry dates (in exchange for fresh dates).