Sayyiduna Abu Rafi' (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) sent a man from Banu Makhzum to collect the zakah, and he said to me: Come with me so that you may also get a share of it. I said: First I will go to the Messenger of Allah (peace and blessings be upon him). So I came to him (peace and blessings be upon him) and asked him, and he (peace and blessings be upon him) said: "The freed slave of a people is counted as one of them, and indeed zakah is not lawful for us."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 928