Sayyiduna Rafi' bin Khadij and Sayyiduna Sahl bin Abi Hathmah (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) "forbade muzabanah, that is, selling the fruit of the date palm for dried dates, but granted a concession to the people of 'araya."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10655