Sahih Muslim 1449 c
The Book of Suckling
The prohibition of marriage to one's stepdaughter and the sister of one's wife
Umm Habiba, the wife of Allah's Messenger (ﷺ), reported that she said to Allah's Messenger (ﷺ): Messenger of Allah, marry my sister 'Azza, whereupon Allah's Messenger (ﷺ) said: Do you like it? She said: Yes, Messenger of Allah, I am not the exclusive wife of yours, and I wish that the person who joins me in good should be my sister. Thereupon Allah's Messenger (ﷺ) said: That is not lawful for me. I said: Messenger of Allah, we discussed that You intend to marry Durrah bint Abu Salama. He (the Prophet) said: You mean the daughter of Abu Salama? She said: Yes, whereupon Allah's Messenger (ﷺ) said: Even if she were not the step-daughter of mine, brought up under my guardianship, she would not have been lawful for me, for she is the daughter of my foster-brother. Thuwaiba gave me suck and to Abu Salama (also), so do not offer to me your daughters and sisters.