Musnad Ahmad 33:855

Muhammad ibn Ubayd narrated to us, Ismail narrated to us, from Salamah ibn Kuhayl, from Ata ibn Abi Rabah, from Jabir ibn Abdullah, who said: "It reached the Messenger of Allah, may Allah bless him and grant him peace, that a man from among his companions had emancipated a slave of his [to be free] after his death, and he had no wealth other than him. So the Messenger of Allah, may Allah bless him and grant him peace, sold the slave for eight hundred [dirhams] and handed it over to his masters."