Islam is an arabic word that means "Total submission of your will to God". It is the same message give to all since Adam through innumerable messengers of God.
Over the time these messages got corrupted and thus the need for messengers from time to time. But with Islam God say that HE has compleated HIS message to the mankind and has perfected HIS religion.
Islam invites all the pupil of Book to cross check what they have been practicing and what according to GOD is THE TRUTH.
BUT GOD also says that it is HE who choses to bestow HIS mercy and show the right path and if he doesnt wish then none can see the TRUTH.
So all we need to do is ask for GUIDANCE from our true CREATOR.
