Hadith
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ ثَوْرِ بْنِ زَيْدٍ الدِّيلِيِّ، عَنْ عَبْدِ اللَّهِ بْنِ عَبَّاسٍ، أَنَّهُ كَانَ يَقُولُ مَا كَانَ فِي الْحَوْلَيْنِ وَإِنْ كَانَ مَصَّةً وَاحِدَةً فَهُوَ يُحَرِّمُ .
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
Sahih · Salim al-Hilali
Muwatta Malik 1275 ·Book 30, Hadith 4·Also available on sunnah.com·