Muwatta 2243

Malik said: whoever frees his slave and makes it final, so that his testimony is admissible, his sanctity is complete, and his inheritance is established, his master may not stipulate on him anything like what he stipulates on his slave, of property or service, nor burden him with any part of enslavement. Because the Messenger said: whoever frees a partner's share in a slave, the slave is valued at a fair price, he gives his partners their shares, and the slave is freed by him. Malik said: therefore, when the slave is entirely his, he has the better claim to complete his manumission, and does not mix it with any part of enslavement. ¹

Belongs to the Muwatta, Book of Manumission and Clientage. Source: the Muwatta. Mentions Malik ibn Anas. Built on in the chapters on manumission (itq).