Urwah narrated that Zainab bint Abi Salamah -whose mother was Umm Salamah, the wife of the Prophet- told him that Umm Habibah bint Abi Sufyan told her that she said:
O Messenger of Allah, marry my sister, the daughter of Abu Sufyan. She said: The Messenger of Allah said: 'Would you like that?' I said: 'Yes; I do not have you all to myself and I would like to share this goodness with my sister.' The Prophet said: 'Your sister is not permissible for me (to marry).' I said: 'By Allah, O Messenger of Allah, we have been saying that you want to marry Durrah bint Abi Salamah.' He said: 'The daughter of Umm Salamah?' I said: 'Yes.' He said: 'By Allah, even if she were not my stepdaughter who is in my care, she would not be permissible for me (to marry), because she is the daughter of my brother through breast-feeding. Thuwaibah breastfed Abu Salamah and I. So do not offer your daughters or sisters to me in marriage.'