(the wife of the Prophet) that while Messenger of Allah ﷺ was with her, she heard a voice of a man asking permission to enter the house of Hafsa. ʿAisha added: I said, "O Messenger of Allah ﷺ! This man is asking permission to enter your house." The Prophet ﷺ said, "I think he is so-and-so," naming the foster-uncle of Hafsa. ʿAisha said, "If so-and-so," naming her foster uncle, "were living, could he enter upon me?" The Prophet ﷺ said, "Yes, for foster suckling relations make all those things unlawful which are unlawful through corresponding birth (blood) relations."
أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ عِنْدَهَا وَأَنَّهَا سَمِعَتْ صَوْتَ رَجُلٍ يَسْتَأْذِنُ فِي بَيْتِ حَفْصَةَ قَالَتْ فَقُلْتُ يَا رَسُولَ اللَّهِ هَذَا رَجُلٌ يَسْتَأْذِنُ فِي بَيْتِكَ فَقَالَ النَّبِيُّ ﷺ أُرَاهُ فُلاَنًا لِعَمِّ حَفْصَةَ مِنَ الرَّضَاعَةِ قَالَتْ عَائِشَةُ لَوْ كَانَ فُلاَنٌ حَيًّا لِعَمِّهَا مِنَ الرَّضَاعَةِ دَخَلَ عَلَىَّ فَقَالَ نَعَمِ الرَّضَاعَةُ تُحَرِّمُ مَا تُحَرِّمُ الْوِلاَدَةُ