Volume 7, Book 62, Number 36:
Narrated ‘Aisha:
(the wife of the Prophet) that while Allah’s Apostle was with her, she heard a voice of a man ask –
ing permission to enter the house of Hafsa. ‘Aisha added: I said, “O Allah’s Apostle! This man is asking
permission to enter your house.” The Prophet said, “I think he is so-and-so,” naming the foster-uncle
of Hafsa. ‘Aisha said, “If so-and-so,” naming her foster uncle, “were living, could he enter upon me?”
The Prophet said, “Yes, for foster suckling relations make all those things unlawful which are unlaw –
ful through corresponding birth (blood) relations.”