{24:27} O you who believe! Do not enter houses other than your own houses until you have asked permission and saluted their inmates; this is better for you, that you may be mindful.

{24:28} But if you do not find any one therein, then do not enter them until permission is given to you; and if it is said to you: Go back, then go back; this is purer for you; and Allah is Cognizant of what you do.