Musannaf Ibn Abi Shaybah

Hazrat Umar (may Allah be pleased with him) said: If a slave belonging to a polytheist becomes Muslim, then that slave will be taken and sold to the Muslims, and its price will be given to its polytheist master.

Hazrat Umar bin Abdul Aziz ordered that the slaves of the dhimmis be sold if they embrace Islam.

Hasan says that if the umm walad of a Christian becomes Muslim, she will try to pay her price, and if a slave-girl accepts Islam, she will be sold.

Hazrat Ata says that if the slave of a dhimmi becomes Muslim, separation will be made between him and his master.

Hasan says that if any of the slaves of the dhimmis becomes a Muslim, he will become free. If the dhimmis buy any Muslim prisoner and then he becomes a Muslim, then that slave will be sold to the Muslims.

Hasan says that if the slave of a dhimmi becomes Muslim, he will be taken to the Amir and sold to the Muslims, and his price will be given to his master.

Hazrat Zuhri says that it has become an established Sunnah that a disbeliever cannot enslave a Muslim.