Sayyiduna Ziyad bin al-Harith al-Suda'i (may Allah be pleased with him), a Companion of the Prophet (peace and blessings be upon him), said: I came to the Prophet (peace and blessings be upon him) and pledged allegiance to him on Islam. Continuing the hadith, he said: Another man came to him (peace and blessings be upon him) and said: Give me some of the sadaqah too. The Messenger of Allah (peace and blessings be upon him) said: "Allah Almighty was not pleased, in the matter of the sadaqat, with the decision of His Prophet or of anyone else, until Allah Almighty Himself decided it; Allah Almighty fixed it in eight categories (portions). If you are one of them, I will give to you," or he said: "We will give you your right."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الصدقات / 13126