Narrated `Amra bint `Abdur-Rahman:
That `Aisha the wife of the Prophet (saws) told her uncle that once, while the Prophet (saws) was in her house, she heard a man asking Hafsa’s (bint umar) permission to enter her house
`Aisha said, “I said, ‘O Allah’s Messenger (saws )! I think the man is Hafsa’s foster uncle.’ ” `Aisha added, “O Allah’s Messenger (saws )! There is a man asking the permission to enter your house.” Allah’s Messenger (saws ) replied, “I think the man is Hafsa’s (bint umar) foster uncle.”
`Aisha (ra) asked, “If so-and-so were living (i.e. her foster uncle) would he be allowed to visit me?” Allah’s Apostle (saws) said, “Yes, he would, as
the foster relations are treated like blood relations (in marital affairs).
Sahih al-Bukhari 2646
In-book : Book 52, Hadith 10