It is narrated from Ata bin Abi Rabah that a man said: O Messenger of Allah (peace and blessings be upon him)! My father has died; should a slave be freed on his behalf? He (peace and blessings be upon him) said: "Yes."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الوصايا / 12641