Musnad Ahmad 426:1

Safwan ibn Isa narrated to us, he said: Al-Harith ibn Abd al-Rahman informed us, from Munir ibn Abdullah, from his father, from Sa’d ibn Abi Dhubab, who said: I came to the Messenger of Allah, peace and blessings of Allah be upon him, and I accepted Islam. I said: "O Messenger of Allah, grant my people [the right to keep] what they possessed of their wealth when they accepted Islam." The Messenger of Allah, peace and blessings of Allah be upon him, did so, and he appointed me over them. Then Abu Bakr, may Allah be pleased with him, appointed me after him, and then Umar appointed me after him.