Sahih Muslim Book 8, Hadith Number 3402.
Chapter: Kitab Al-Rada’a-Book pertaining to fosterage.
This hadith has been narrated on the authority of Hisham with the same chain of transmitters (and the words are): “The brother of Abu’l-Qu’ais sought permission from her (‘Aisha) (to enter the house). The rest is the same.