Abu Dawud
Book Of Emancipation Of Slaves
Book Number: 024 / Hadith Number: 3926
Narated By N/A : Abu Hurairah reported the Prophet (may peace be upon him) as saying: If anyone emancipates a share in his slave, he should completely emancipate him if he has money; but if he has none, the slave will be required to work (to pay for his free-dom), but he must not be overburdened.