Hizam bin Hakim bin Hizam (may Allah have mercy on him) narrated from his father, who said: I bought some grain from the charity grain from the Messenger of Allah (peace and blessings be upon him), and made a profit on it before I had received it. So I said to myself: I will not sell it until I ask the Messenger of Allah (peace and blessings be upon him) about it. He (peace and blessings be upon him) said: "Do not sell it until you have taken possession of it."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 3097