ভূমিকা
Do not enter houses other than your own houses until you have asked permission and saluted those in them. That is better for you, so that you might be admonished.” Commentary: The Arabic word /’istanas/ means to ask permission and to declare one’s entrance or coming in.
According to some Islamic narrations, entrance to a place can be stated by saying Allah’s name, or by footfall, or by greeting calling hello, and the like.[^1] Some one asked the Prophet (p.b.u.h.) whether he had to ask permission for entering his mother's house.
He said: [^1] Nur-uth-Thaqalyn, the Commentary “Yes.” That man said: “Except her no one lives in the house, and except me no servant she has!” The Prophet (p.b.u.h.) said: “Do you like to see your mother nude?”The man said: “No.” Then the Prophet (p.b.u.h.) said: “So ask permission.” There is another narration in which the Prophet (p.b.u.h.) prohibited men from entering the houses in which women’s guardians are not present.[^1] In narrations we read that we must ask permission for three times so that those people in the house may have time enough to get ready.
(Of course, permission is asked only for entering others’ house.