سنن النسائي

It was narrated from Umm Habibah that she said: "O Messenger of Allah, what do you think of my sister?" He said: "What for?" She said: "For marriage." He said: "Would you like that?" She said: "Yes; I do not have you all to myself, and I would like to share this goodness with my sister." He said: "She is not permissible for me (to marry)." She said: "But I heard that you want to marry Durrah, the daughter of Umm Salamah." He said: "The daughter of Umm Salamah?" She said: "Yes." He said: "By Allah, even if she were not my stepdaughter she would not be permissible for me (to marry), because she is the daughter of my brother through breast-feeding. Do not offer your daughters and sisters to me in marriage."