Maliks Muwatta Book 030, Hadith Number 002.

Section : Suckling of the Young.

Yahya related to me from Malik from Hisham ibn Urwa from his father that A'isha, umm al-muminin said, "My paternal uncle by suckling came to me and I refused to give him permission to enter until I had asked the Messenger of Allah, may Allah bless him and grant him peace, about it. The Messenger of Allah, may Allah bless him and grant him peace, came and I asked him about it. He said, 'He is your paternal uncle, so give him permission.' So I said, 'Messenger of Allah! The woman nursed me not the man.' He said, 'He is your paternal uncle, so let him enter.'"

A'isha said, "That was after the veil had been imposed on us."

A'isha added, "What is haram by birth is made haram by suckling."