Marriage
Malik :: Book 28 : Hadith 28.19.43
Yahya related to me from Malik that he heard Rabia ibn Abd ar-Rahman say that a slave could marry four women.
Malik said, "This is the best of what I have heard about the matter."
Malik said, "The slave differs with the muhallil if the slave is given permission by his master for his ex-wife. If his master does not give him permission, he separates them. The muhallil is separated in any case if he intends to make the woman halal by marriage."
Malik said, "When a slave is owned by his wife or a husband owns his wife, the possession of each of them is rendered void without divorce. If a man, for instance, is married to a slave-girl, and then he buys her, he must divorce her as a matter of course. They can then re-marry. If they re-marry afterwards, that separation was not divorce."
Malik said, "When a slave is freed by his wife who owns him and she is in the idda-period from him, they can only return to each other after she has made another marriage."