Musnad Abu Ya'la al-Mawsili 24:1

Ali ibn al-Ja'd narrated to us, Shu'bah narrated to us, from Ali ibn Zayd, who said: I heard Zurarah ibn Awfa narrating from a man of his people called Abu Malik, or Ibn Malik, that he heard the Prophet, peace and blessings of Allah be upon him, saying: "Whoever takes in an orphan among Muslims into his food and drink until he becomes independent of him, Paradise becomes mandatory for him, absolutely. And whoever reaches his parents, or one of them, then does not treat them with goodness, then enters the Fire, may Allah distance him. And whichever Muslim frees a Muslim slave, it will be his ransom from the Fire."