(7) باب الشَّهَادَةِ عَلَى الأَنْسَابِ وَالرَّضَاعِ الْمُسْتَفِيضِ وَالْمَوْتِ الْقَدِيمِ
Narrated `Amra bint `Abdur-Rahman:
That `Aisha the wife of the Prophet (ﷺ) told her uncle that once, while the Prophet (ﷺ) was in her house, she heard a man asking Hafsa's permission to enter her house. `Aisha said, "I said, 'O Allah's Messenger (ﷺ)! I think the man is Hafsa's foster uncle.' " `Aisha added, "O Allah's Messenger (ﷺ)! There is a man asking the permission to enter your house." Allah's Messenger (ﷺ) replied, "I think the man is Hafsa's foster uncle." `Aisha said, "If so-and-so were living (i.e. her foster uncle) would he be allowed to visit me?" Allah's Apostle said, "Yes, he would, as the foster relations are treated like blood relations (in marital affairs).
Reference: Sahih al-Bukhari 2646
In-book reference: Book 52, Hadith 10
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 48, Hadith 814