Al-Lu'lu Wal-Marjan 921 — The Book of Ar-Rada' (Suckling foster relations)

A'isha Narrated from:

Once the Prophet صلى الله عليه وسلم came to me while a man was in my house. He said, “O ‘Âisha ! Who is this (man)?” I replied, “My foster suckling brother.” He said, “O ‘Âisha! Be sure about your foster suckling brothers, as suckling foster-ship is only valid if it takes place in the suckling period (before two years of age as the child sucks with hunger).” ( Sahîh Al-Bukhârî, Hadîth No. 815, Vol. 3)