If you’ve ever encountered two Muslims greeting each other, you would have heard the Islamic greeting:
The first person says “Assalamu Alaykum Wa Rahmatullaahi wa barakatuh” (peace and mercy and blessings of God be upon you), which is often shortened to ‘Assalamu Alaykum’ (peace be upon you),
The second person replies as ‘wa alaykum assalam’ (and peace be upon you also).
In Islam, this greeting is used for greeting and parting and so it is the English equivalent of ‘hello’,’good day’ as a greeting or ‘goodbye’,’farewell’ while parting. Generally, the Islamic Greeting is associated with the shaking of the right hands. In some instances two or three light cheek-to-cheek kisses, alternating side (practiced mostly amongst the Arabs) or a very light hug is seen.
However, the shaking of hands and cheek kisses between opposite genders is to be avoided at all costs since Islam forbids unnecessary contact between two people from opposite genders.
How a Muslim should greet a non-Muslim is of mixed opinions. Some believe that the Islamic greeting should not extend to non-Muslims because if you greet a non-Muslim with the Islamic greeting, chances are they would not know of its reply so it’s better to avoid it.
However, if a non-Muslim initiates it, then there is no harm in replying with the greeting since it is merely a good prayer for the other person.