(24:27) O believers! Do not enter houses other than your own until you have sought permission and said greetings of peace to the occupants; this is better for you, so that you may be mindful.
(4:86) And when you are greeted with a greeting, greet [in return] with one better than it or [at least] return it [in a like manner]. Indeed, Allah is ever, over all things, an Accountant.
(4:94) O you who have believed, when you go forth [to fight] in the cause of Allah, investigate; and do not say to one who gives you [a greeting of] peace “You are not a believer,” aspiring for the goods of worldly life; for with Allah are many acquisitions. You [yourselves] were like that before; then Allah conferred His favor upon you, so investigate. Indeed Allah is ever, with what you do, Acquainted.
(33:56) Indeed Allah and His angels send blessings on the Prophet. O believers, call for [Allah’s] blessings on him and salute him with all respect.
(24:61) There is no blame on the blind, nor there is blame on the lame, nor there is blame on the sick, to eat at your table. Nor shall it be an offense for you to eat in the houses of your own children, or your fathers, or your mothers, or your brothers, or your sisters, or your paternal uncles, or your paternal aunts, or your maternal uncles, or your maternal aunts, or your sincere friends, or in houses with the keys of which you are entrusted. There is no blame on you whether you eat together or apart; however, when you enter the houses, you should greet one another with greeting of peace prescribed by Allah blessed and pure. Thus Allah makes His revelations clear to you, so that you may grow in understanding.
(56:88) Then if the dying person is one of those near to Us,
(56:89) for them there is comfort and bounty, and a garden of bliss.
(56:90) And if he be one of the right hand,
(56:91) he is greeted with salutation: “Peace be upon you,” from those of the right hand.
(56:92) And if he is one of the mistaken rejecters,
(56:93) he is welcomed with scalding water,
(56:94) and burning in hellfire.
(56:95) Surely this is an absolute truth.
(56:96) Therefore, glorify the name of your Lord (Rabb), Who is the Greatest.