Sahl bin Abi Hathmah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) forbade "selling the fruit on the tree for dried dates," but granted a concession in the 'ariyyah sale, that "the fruit on the tree may be sold for dried dates by estimation, so that its owners may eat fresh dates."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10656