An-Nur 24:27

<h2>Seeking Permission and the Etiquette of entering Houses</h2><p>This is the Islamic etiquette. Allah taught these manners (of seeking permission) to His believing servants and commanded them not to enter houses other than their own until they had asked permission, i.e., to ask for permission before entering and to give the greeting of Salam after asking. One should seek permission three times, and if permission is given, (he may enter), otherwise he should go away.It was reported in the Sahih that when Abu Musa asked `Umar three times for permission to enter and he did not give him permission, he went away. Then `Umar said, "Did I not hear the voice of `Abdullah bin Qays asking for permission to enter Let him come in." So they looked for him, but found that he had gone. When he came later on, `Umar said, "Why did you go away" He said, "I asked for permission to enter three times, but permission was not given to me, and I heard the Prophet say,</p><p>«إِذَا اسْتَأْذَنَ أَحَدُكُمْ ثَلَاثًا فَلَمْ يُؤْذَنْ لَهُ فَلْيَنْصَرِفْ»</p><p>(If any one of you asks for permission three times and it is not given, then let him go away.)" `Umar said, "You should certainly …

O ye who believe! Enter not houses other than your own without first announcing your presence and invoking peace upon the folk thereof. That is better for you, that ye may be heedful.

O ye who believe! enter not houses other than your own, until ye have asked permission and saluted those in them: that is best for you, in order that ye may heed (what is seemly).

O you who believe! Enter not houses other than your own, until you have asked permission and greeted those in them, that is better for you, in order that you may remember.

O you who believe! Do not enter homes other than your own, until you have asked permission and greeted their occupants. That is better for you, that you may be aware.