Yahya related to me from Malik from Ibn Shihab from Amr ibn ash- Sharid that Abdullah ibn Abbas was asked whether, if a man had two wives, and one of them nursed a slave-boy, and the other had nursed a slave-girl, could the slave-boy marry the slave-girl. He said, "No. The husband is the same."
Muwatta Malik Book 30, Hadith 5
← Previous Hadith Yahya related to me from Malik from Thawr ibn Zayd ad-Dili that Abdullah ibn Abbas said, "The milk which a child under two years old sucks, even if it is only one suck, makes the foster relatives haram."

Muwatta Malik Book 30, Hadith 4 Next Hadith → Yahya related to me from Malik from Nafi that Abdullah ibn Umar said, "There is no kinship by suckling except for a person who is nursed when he is small. There is no kinship by suckling over the age of two years."

Muwatta Malik Book 30, Hadith 6