Sayyiduna Abu Rafi' (may Allah be pleased with him) said: The Prophet (peace and blessings be upon him) sent a man from Banu Makhzum to collect charity, and he said to Sayyiduna Abu Rafi' (may Allah be pleased with him): "Accompany me; whatever share I get, you will get too." Sayyiduna Abu Rafi' (may Allah be pleased with him) said: "No, not until I ask him (peace and blessings be upon him)." So he came to the Prophet (peace and blessings be upon him) and asked, and he (peace and blessings be upon him) said: "Charity is not lawful for us, and the freed slaves of a people are from among them."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الصدقات / 13242