It is narrated from Sayyiduna Jabir (may Allah be pleased with him): The Messenger of Allah (peace and blessings be upon him) forbade selling fresh dates for dried dates and grapes for raisins, and he granted a concession in 'araya. 'Araya is that a Bedouin comes to his cousin or to someone of his household, and he grants him the fruit of one or two date palms which has not yet ripened, while he intends to set out on a journey; then there is no harm in his selling it for dried dates.
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 1735