مُوَطَّأُ مَالِكٍ
Muwatta Malik 1280
Suckling
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ يَقُولُ لاَ رَضَاعَةَ إِلاَّ لِمَنْ أُرْضِعَ فِي الصِّغَرِ وَلاَ رَضَاعَةَ لِكَبِيرٍ .
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."
Arabic/English book reference: Book 30, Hadith 6