Sahih Muslim Book 10, Hadith Number 3693.

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

Ibn Umar (Allah be pleased them) reported Allah’s Messenger (may peace be upon him) having forbidden Muzabana, and Muzabana implies the selling of fresh dates for dry dates by measuring them out and the selling of raisins by measure for grapes.