It is narrated from Hazrat Aisha (may Allah be pleased with her) that once the Prophet (peace and blessings be upon him) came to her place and there was a man present there. It seemed that the Prophet (peace and blessings be upon him) was displeased by this. She said, "O Messenger of Allah! This is my brother." The Prophet (peace and blessings be upon him) said, "Make sure to verify who your brothers are, for the relationship of suckling is due to hunger (that is, the period is two and a half years, and during this time the child's hunger is satisfied by that milk)."