Sahih Bukhari Volume 7, Book 62, Hadith Number 40.

Narrated By ‘Aisha : That Aflah the brother of Abu Al-Qu’ais, her foster uncle, came, asking permission to enter upon her after the Verse of Al-Hijab (the use of veils by women) was revealed. ‘Aisha added: I did not allow him to enter, but when Allah’s Apostle came, I told him what I had done, and he ordered me to give him permission.