Narrated Amra bint 'Abdur-Rahman:

That 'Aisha the wife of the Prophet told her uncle that once, while the Prophet was in her house, she heard a man asking Hafsa's permission to enter her house. 'Aisha said, "I said, 'O Allah's Apostle! I think the man is Hafsa's foster uncle.' " 'Aisha added, "O Allah's Apostle! There is a man asking the permission to enter your house." Allah's Apostle 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 ﷺ said, "Yes, he would, as the foster relations are treated like blood relations (in marital affairs)."

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، أَخْبَرَنَا مَالِكٌ، عَنْ عَبْدِ اللَّهِ بْنِ أَبِي بَكْرٍ، عَنْ عَمْرَةَ بِنْتِ عَبْدِ الرَّحْمَنِ، أَنَّ عَائِشَةَ ـ رضى الله عنها ـ زَوْجَ النَّبِيِّ ﷺ أَخْبَرَتْهَا أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ عِنْدَهَا، وَأَنَّهَا سَمِعَتْ صَوْتَ رَجُلٍ يَسْتَأْذِنُ فِي بَيْتِ حَفْصَةَ. قَالَتْ عَائِشَةُ فَقُلْتُ يَا رَسُولَ اللَّهِ أُرَاهُ فُلاَنًا. لِعَمِّ حَفْصَةَ مِنَ الرَّضَاعَةِ. فَقَالَتْ عَائِشَةُ يَا رَسُولَ اللَّهِ، هَذَا رَجُلٌ يَسْتَأْذِنُ فِي بَيْتِكَ. قَالَتْ فَقَالَ رَسُولُ اللَّهِ ﷺ " أُرَاهُ فُلاَنًا ". لِعَمِّ حَفْصَةَ مِنَ الرَّضَاعَةِ. فَقَالَتْ عَائِشَةُ لَوْ كَانَ فُلاَنٌ حَيًّا ـ لِعَمِّهَا مِنَ الرَّضَاعَةِ ـ دَخَلَ عَلَىَّ فَقَالَ رَسُولُ اللَّهِ ﷺ " نَعَمْ، إِنَّ الرَّضَاعَةَ تُحَرِّمُ مَا يَحْرُمُ مِنَ الْوِلاَدَةِ ".