The Book of Suckling · The daughter of one's brother through breastfeeding is forbidden in marriage
Arabic
وَحَدَّثَنَا هَارُونُ بْنُ سَعِيدٍ الأَيْلِيُّ، وَأَحْمَدُ بْنُ عِيسَى، قَالاَ حَدَّثَنَا ابْنُ وَهْبٍ، أَخْبَرَنِي مَخْرَمَةُ بْنُ بُكَيْرٍ، عَنْ أَبِيهِ، قَالَ سَمِعْتُ عَبْدَ اللَّهِ بْنَ مُسْلِمٍ، يَقُولُ سَمِعْتُ مُحَمَّدَ بْنَ مُسْلِمٍ، يَقُولُ سَمِعْتُ حُمَيْدَ بْنَ عَبْدِ الرَّحْمَنِ، يَقُولُ سَمِعْتُ أُمَّ سَلَمَةَ، زَوْجَ النَّبِيِّ صلى الله عليه وسلم تَقُولُ قِيلَ لِرَسُولِ اللَّهِ صلى الله عليه وسلم أَيْنَ أَنْتَ يَا رَسُولَ اللَّهِ عَنِ ابْنَةِ حَمْزَةَ . أَوْ قِيلَ أَلاَ تَخْطُبُ بِنْتَ حَمْزَةَ بْنِ عَبْدِ الْمُطَّلِبِ قَالَ " إِنَّ حَمْزَةَ أَخِي مِنَ الرَّضَاعَةِ " .
English translation
Umm Salama (Allah be pleased with her), the wife of Allah's Messenger (ﷺ), said: It was said to the Messenger of Allah (ﷺ): Is not the daughter of Hamza a suitable match for you? Or it was said: Why don't you propose to marry the daughter of Hamza, the son of Abd al-Muttalib? Thereupon he said: Hamza is my brother by reason of fosterage.
'Ali (Allah be pleased with him) reported having said this: Messenger of Allah, why is it that you select (your wife) from among the Quraish, but you ignore us (the nearest of the kin)? Thereupon he said: Have you anythi…
Ibn Abbas (Allah be pleased with them) reported: It was proposed that he (the Holy Prophet) be married to the daughter of Hamza, whereupon he said: She is not lawful for me for she is the daughter of my foster-brother, a…