Maliks Muwatta Book 054, Hadith Number 001.

Section : Asking Permission to Enter.

Malik related to me from Safwan ibn Sulaym from Ata ibn Yasar that the Messenger of Allah, may Allah bless him and grant him peace, was questioned by a man who said, "Messenger of Allah, shall I ask permission of my mother to enter?" He said, "Yes " The man said, "I live with her in the house". The Messenger of Allah, may Allah bless him and grant him peace, said "Ask her permission." The man said, "I am her servant." The Messenger of Allah. may Allah bless him and grant him peace, said, "Ask her permission. Do you want to see her naked?" He said, "No." He said, "Then ask her permission."