Musannaf Ibn Abi Shaybah 19866 — A man married to a slave woman

Ibrahim (may Allah have mercy on him) said: When a slave woman is given one divorce and then gains her freedom before her waiting period is completed, she observes the waiting period of a free woman. If she is given two divorces and then gains her freedom, she observes the waiting period of a slave woman, because she has become irrevocably separated from him. The same ruling applies to the slave woman whose husband dies and who then also gains her freedom.