Literally means 'Peace be upon you'
It is the prescribed Islam
used by muslim
s and is responded to by saying Walaikum Asalam
which means Peace be upon you too
This form of greeting is said to carry a reward
of 10 blessings
can often be extended thus -
Salamun Alaikum Warahmatullahi Wabarakatuhu
which means 'Peace be upon you and the mercy and blessings of Allah'
(The extended greeting is said to carry a reward of 30 blessings)
It is stated in the Quran
that when the people of heaven
shall be asked by Allah
(The almighty) to enter it, they will be welcomed therein with this greeting of Peace.