Abdullah bin Umar (may Allah be pleased with them both) narrates: A man came from Syria bringing olive oil. Among the traders who bid for it, I also participated in the bidding until I bought that oil from him. Then a man came to me and started offering me a higher price until he satisfied me. I was about to strike my hand with his (i.e., finalize the deal) when suddenly someone grabbed my wrist from behind. I turned around and saw that it was Zaid bin Thabit (may Allah be pleased with him). He said to me: "Do not sell it until you have transferred it to your specific place, because the Prophet (peace and blessings of Allah be upon him) forbade this." (Abdullah bin Umar, may Allah be pleased with them both, says) So I withheld my hand.