Sayyiduna Hakim bin Hizam (may Allah be pleased with him) said: I said: O Messenger of Allah (peace and blessings be upon him)! I buy these trade goods; what of them is lawful for me and what is unlawful? He (peace and blessings be upon him) said: "O son of my brother! Do not sell anything at all before taking possession of it."
(b) Aban said in the hadith: When you buy goods, "do not sell them before taking possession of them."
This chain is hasan (good) and connected.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10685