Aflah asked the permission to visit me but I did not allow him. He said, "Do you veil yourself before me although I am your uncle?" ʿAisha said, "How is that?" Aflah replied, "You were suckled by my brother's wife with my brother's milk." I asked Messenger of Allah ﷺ about it, and he said, "Aflah is right, so permit him to visit you."  

قَالَتِ اسْتَأْذَنَ عَلَىَّ أَفْلَحُ فَلَمْ آذَنْ لَهُ فَقَالَ أَتَحْتَجِبِينَ مِنِّي وَأَنَا عَمُّكِ فَقُلْتُ وَكَيْفَ ذَلِكَ قَالَ أَرْضَعَتْكِ امْرَأَةُ أَخِي بِلَبَنِ أَخِي فَقَالَتْ سَأَلْتُ عَنْ ذَلِكَ رَسُولَ اللَّهِ ﷺ فَقَالَ صَدَقَ أَفْلَحُ ائْذَنِي لَهُ  

The Prophet ﷺ said about Hamza's daughter, "I am not legally permitted to marry her, as foster relations are treated like blood relations (in marital affairs). She is the daughter of my foster brother."  

قَالَ النَّبِيُّ ﷺ فِي بِنْتِ حَمْزَةَ لاَ تَحِلُّ لِي يَحْرُمُ مِنَ الرَّضَاعِ مَا يَحْرُمُ مِنَ النَّسَبِ هِيَ بِنْتُ أَخِي مِنَ الرَّضَاعَةِ  

That ʿAisha 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. ʿAisha said, "I said, 'O Messenger of Allah ﷺ! I think the man is Hafsa's foster uncle.' " ʿAisha added, "O Messenger of Allah ﷺ! There is a man asking the permission to enter your house." Messenger of Allah ﷺ replied, "I think the man is Hafsa's foster uncle." ʿAisha 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).  

أَنَّ عَائِشَةَ ؓ 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 لِعَمِّهَا مِنَ الرَّضَاعَةِ دَخَلَ عَلَىَّ فَقَالَ رَسُولُ اللَّهِ ﷺ نَعَمْ إِنَّ الرَّضَاعَةَ تُحَرِّمُ مَا يَحْرُمُ مِنَ الْوِلاَدَةِ  

Once the Prophet ﷺ came to me while a man was in my house. He said, "O ʿAisha! Who is this (man)?" I replied, "My foster brothers" He said, "O ʿAisha! Be sure about your foster brothers, as fostership is only valid if it takes place in the suckling period (before two years of age).  

دَخَلَ عَلَىَّ النَّبِيُّ ﷺ وَعِنْدِي رَجُلٌ قَالَ يَا عَائِشَةُ مَنْ هَذَا قُلْتُ أَخِي مِنَ الرَّضَاعَةِ قَالَ يَا عَائِشَةُ انْظُرْنَ مَنْ إِخْوَانُكُنَّ فَإِنَّمَا الرَّضَاعَةُ مِنَ الْمَجَاعَةِ