Musnad Ahmad 775:16

Abu Abd al-Rahman said: And it was in my father’s book: Yazid ibn Harun narrated to us, Fā’id ibn Abd al-Rahman informed us, he said: I heard Abdullah ibn Abi Awfa say: I was with the Messenger of Allah, may Allah bless him and grant him peace, when a boy came to him and said: "O Messenger of Allah, there is an orphan boy here, who has a widowed mother and an orphan sister. Feed us from what Allah the Exalted has fed you; may Allah give you from what He has, until you are satisfied." Then he mentioned the rest of the hadith in full.