Salim bin Abdullah (may Allah have mercy on him) narrates from his father (Sayyiduna Abdullah bin Umar (may Allah be pleased with them both)): I heard the Messenger of Allah (peace and blessings be upon him) say: "Whoever buys palm trees after they have been pollinated, their fruit belongs to the one who sold them, unless the buyer stipulates (otherwise); and whoever buys a slave, the slave's property belongs to the one who sold him, unless the buyer stipulates (otherwise)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10757