Al-Kāfi - Volume 7 > Another Chapter
Hadith #1

1- عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ سَهْلِ بْنِ زِيَادٍ عَنْ مَرْوَكِ بْنِ عُبَيْدٍ عَنْ أَبِي الْحَسَنِ الرِّضَا (عَلَيْهِ السَّلام) قَالَ دَخَلْتُ عَلَيْهِ وَسَلَّمْتُ وَقُلْتُ جُعِلْتُ فِدَاكَ مَا تَقُولُ فِي رَجُلٍ مَاتَ وَلَيْسَ لَهُ وَارِثٌ إِلا أَخٌ لَهُ مِنَ الرَّضَاعَةِ يَرِثُهُ قَالَ نَعَمْ أَخْبَرَنِي أَبِي عَنْ جَدِّي أَنَّ رَسُولَ اللهِ (صَلَّى اللهُ عَلَيْهِ وَآلِه) قَالَ مَنْ شَرِبَ مِنْ لَبَنِنَا أَوْ أَرْضَعَ لَنَا وَلَداً فَنَحْنُ آبَاؤُهُ.

1. A number of our people have narrated from Sahl ibn Ziyad from Marwak ibn ‘Ubayd who has narrated the following: “I once visited abu al-Hassan al-Rida’, ‘Alayhi al-Salam. I offered greeting of peace and asked saying, ‘I pray to Allah to keep my soul in service for your cause. What do you say about the case of a man who dies and has no other heirs except a brother who is due to breastfeeding; can he inherit him? He (the Imam) said, ‘Yes, my father narrated to me from my grandfather, the Messenger of Allah, O Allah, grant compensation to Muhammad and his family worthy of their services to Your cause, who has said, ‘One who drinks from our milk or gives milk to one of our children, we then are his fathers.”’ (This is perhaps to protect one from tyrants).