Al-Kāfi

Hadith 1738
breastfeedingmilk-kinship
3- عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنِ ابْنِ أَبِي نَجْرَانَ عَنْ عَبْدِ اللهِ بْنِ سِنَانٍ قَالَ سَأَلْتُ أَبَا عَبْدِ اللهِ (عَلَيْهِ السَّلام) عَنْ لَبَنِ الْفَحْلِ قَالَ مَا أَرْضَعَتِ امْرَأَتُكَ مِنْ لَبَنِ وَلَدِكَ وَلَدَ امْرَأَةٍ أُخْرَى فَهُوَ حَرَامٌ.
3. Ali ibn Ibrahim has narrated from his father from ibn abu Najran from ‘Abd Allah ibn Sinan who has said the following: “This is concerning my question before abu ‘Abd Allah (a.s.), about the milk of ‘impregnating agent’. He (the Imam) said, ‘It is the milk from your wife from your milk and the milk of your children given to the child of another woman and that child is unlawful (for marriage).”’
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī