Musnad Ahmad 746:1

Bahz and ‘Affan narrated to us, they said: Hammad ibn Salamah narrated to us. ‘Affan said in his narration: ‘Ali ibn Zayd informed us, from Zurarah ibn Awfa, from Malik ibn ‘Amr al-Qushayri, who said: I heard the Messenger of Allah (peace and blessings of Allah be upon him) saying: "Whoever frees a Muslim slave, it is his ransom from the Fire." ‘Affan said: "In place of every bone of the bones of the one he freed, there is a bone of his own bones. And whoever reaches one of his parents, then is not forgiven, may Allah distance him. And whoever takes in an orphan from between two Muslim parents,"—‘Affan said: "to his food and his drink until Allah makes him self-sufficient, Paradise becomes mandatory for him."