Musnad Ahmad 788:28

Hammad ibn Usamah narrated to us, from Burayd ibn Abdullah ibn Abi Burdah, from his grandfather Abu Burdah, from Abu Musa, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, the trustworthy treasurer who gives what he is commanded to give, completely, fully, and with a good soul, until he delivers it to the one he was commanded to give it to, is one of the two who give charity."