the one purchased was not a bed for him, but she is prohibited to him by his use of her sister for intercourse. If he removes the woman with whom he had intercourse from his ownership, and then she returns to him before he has intercourse with her sister, she is lawful for him, and her sister is prohibited to him because her sister is his bed.

Section: The ruling on physical contact with slave girls in matters other than the vagina, and looking at the vagina with desire, regarding the prohibition of the sister, is like the ruling on the prohibition of the step-daughter. The correct view is that it does not prohibit [the other sister], because permissibility is established by His saying: "or those whom your right hands possess" (Qur'an 4:3). The exception to this is established only by His saying: "and that you join two sisters [in wedlock]" (Qur'an 4:23). What is meant by this is joining them in the marriage contract or in intercourse, and neither of these, nor that which is in their meaning, is found here.

Section: If he has intercourse with his slave girl, then wishes to marry her sister, Ahmad has been asked about this and said: "He shall not join two sisters who are slave girls [in marriage]." It is possible he meant that the marriage is not valid. This is one of the narrations from Malik. Al-Qadi said: "This is the apparent meaning of Ahmad's words, because a woman becomes a bed through marriage, so it is not permissible for it to occur upon the bed of the sister, just like intercourse. And because it is an act involving the sister that contradicts the permissibility of her sister who is used for intercourse, so it is not permissible, just like intercourse." It is possible that the marriage is valid, but the married one is not made permissible until her sister is prohibited. This is the school of Abu Hanifa. Abu al-Khattab said: "This is the apparent meaning of Ahmad's words, because it is a cause by which intercourse is made permissible, so it is permissible for it to occur upon the intercourse of the sister, and it does not make [the sister] permissible, like buying." Al-Shafi'i said: "The marriage is valid, the married one becomes permissible for him, and her sister is prohibited, because marriage is stronger than intercourse by ownership of the right hand; thus, when they coexist, the stronger one must be given precedence." The argument for the first position is what we have mentioned.