Malik said, "The generally agreed on way of doing things in ourcommunity about a mudabbar is that the owner cannot sell him or changethe position in which he has put him. If a debt overtakes the master,his creditors cannot sell the mudabbar as long as the master is alive.If the master dies and has no debts, the mudabbar is included in thethird (of the bequest) because he expected his work from him as longas he lived. He cannot serve him all his life, and then he frees himfrom his heirs out of the main portion of his property when he dies.If the master of the mudabbar dies and has no property other than him,one third of him is freed, and two thirds of him belong to the heirs.If the master of the mudabbar dies and owes a debt which encompassesthe mudabbar, he is sold to meet the debt because he can only be freedin the third (which is allowed for bequest) ."He said, "Ifthe debt only includes half of the slave, half of him is sold for thedebt. Then a third of what remains after the debt is freed. "Malik said, "It is not permitted to sell a mudabbar and it is notpermitted for anyone to buy him unless the mudabbar buys himself fromhis master. He is permitted to do that. Or else some one gives themaster of the mudabbar money and his master who made him a mudabbarfrees him. That is also permitted for him."Malik said, "Hiswala' belongs to his master who made him a mudabbar."Maliksaid, "It is not permitted to sell the service of a mudabbar becauseit is an uncertain transaction since one does not know how long hismaster will live. That is uncertain and it is not good."Malik spoke about a slave who was shared between two men, and one ofthem made his portion mudabbar. He said, "They estimate his valuebetween them. If the one who made him mudabbar buys him, he is allmudabbar. If he does not buy him, his tadbir is revoked unless the onewho retains ownership of him wishes to give his partner who made himmudabbar his value. If he gives him to him for his value, that isbinding, and he is all mudabbar."Malik spoke about thechristian man who made a christian slave of his mudabbar and then theslave became muslim. He said, "One separates the master and the slave,and the slave is removed from his christian master and is not solduntil his situation becomes clear. If the christian dies and has adebt, his debt is paid from the price of the slave unless he has inhis estate what will pay the debt. Then the mudabbar is set free."
USC-MSA web (English) reference: Book 40, Hadith 6