Sahih Bukhari
Witnesses
Volume: 003 / Book Number: 048 / Hadith Number: 815
Narrated Aisha:
Once the Prophet came to me while a man was in my house. He said, "O 'Aisha! Who is this (man)?" I replied, "My foster brothers" He said, "O 'Aisha! Be sure about your foster brothers, as fostership is only valid if it takes place in the suckling period (before two years of age)."