It is narrated from Hazrat Abu Rafi’ (may Allah be pleased with him) that once Arqam (may Allah be pleased with him) or his son passed by me; they had been appointed for the collection of zakat. He invited me to go with him. I presented myself before the Prophet (peace and blessings be upon him) and asked him about this matter. The Prophet (peace and blessings be upon him) said: O Abu Rafi’! Zakat is forbidden for Muhammad and the family of Muhammad (peace and blessings be upon him), and the freed slave of a people is counted among them.
Hadith Referenceمسند احمد / من مسند القبائل / 27182