Musannaf Ibn Abi Shayba 13:1803

Abu Bakr narrated to us, he said: Abd al-Salam ibn Harb narrated to us, from Mughira, from Hammad, from Ibrahim, regarding a man who emancipated a slave of his during his illness, then died while he had a debt and possessed no wealth other than him. He said: He (the slave) shall work for his value. If the value is greater than the debt, the creditors shall take their debt. And one shall look at what remains of the thing; the heirs shall have two-thirds of it, and he (the slave) shall have one-third of it.