Muwatta Malik, Book 30, Hadith 13 (USC-MSA)

Yahya related to me from Malik that Abdullah ibn Dinar said, "A man came to Abdullah ibn Umar when I waswith him at the place where judgments were given and asked him about the suckling of an older person. Abdullah ibn Umar replied, 'A man came to Umar ibn al-Khattab and said, 'I have a slave-girl and I used to have intercourse with her. My wife went to her and suckled her. When I went to the girl, my wife told me to watch out, because she had suckled her!' Umar told him to beat his wife and to go to his slave-girl because kinship by suckling was only by the suckling of the young.' "

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ عَبْدِ اللَّهِ بْنِ دِينَارٍ، أَنَّهُ قَالَ جَاءَ رَجُلٌ إِلَى عَبْدِ اللَّهِ بْنِ عُمَرَ وَأَنَا مَعَهُ عِنْدَ دَارِ الْقَضَاءِ يَسْأَلُهُ عَنْ رَضَاعَةِ الْكَبِيرِ فَقَالَ عَبْدُ اللَّهِ بْنُ عُمَرَ جَاءَ رَجُلٌ إِلَى عُمَرَ بْنِ الْخَطَّابِ فَقَالَ إِنِّي كَانَتْ لِي وَلِيدَةٌ وَكُنْتُ أَطَؤُهَا فَعَمَدَتِ امْرَأَتِي إِلَيْهَا فَأَرْضَعَتْهَا فَدَخَلْتُ عَلَيْهَا فَقَالَتْ دُونَكَ فَقَدْ وَاللَّهِ أَرْضَعْتُهَا ‏.‏ فَقَالَ عُمَرُ أَوْجِعْهَا وَأْتِ جَارِيتَكَ فَإِنَّمَا الرَّضَاعَةُ رَضَاعَةُ الصَّغِيرِ ‏.‏

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also referenced under: Book 30, Hadith 1288 (In-Book)