Abd al-Rahman, one of Banu Harithah, narrates from his grandmother Umm Bujayd (may Allah be pleased with her), who was among those who gave the pledge of allegiance to the Messenger of Allah (peace and blessings be upon him). She said: O Messenger of Allah! By Allah, it sometimes happens that a poor person stands at my door but I find nothing to give him. The Messenger of Allah (peace and blessings be upon him) said to her: "If you find nothing at all, then send him back after giving him a burnt hoof."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7750