Sayyida Umm Salama (may Allah be pleased with her) narrates that Sayyida Umm Habiba (may Allah be pleased with her) said: O Messenger of Allah! Do you have an interest in my sister? He said: What should I do with her? She said: You should marry her. He said: Your sister? She said: Yes! He said: Do you like that? She replied: I am not the only one who is your wife, and I would prefer that my sister also share in this honor (of being your wife) with me. He said: She is not lawful for me (because two sisters cannot be married at the same time). Umm Habiba (may Allah be pleased with her) said: By Allah! I have come to know that you have sent a marriage proposal to Durrah or Dhurrah. The Prophet (peace and blessings be upon him) asked: To the daughter of Umm Salama? She replied: Yes! He said: By Allah! Even if she were not my stepdaughter (the daughter of my wife from a previous husband), she would still not be lawful for me, because she is the daughter of my foster brother. Both her father and I were suckled by Thuwaibah, so do not offer your daughters and sisters to me (for marriage).