So, because you are lukewarm, and neither cold nor hot, I will spew you out of my mouth. A persons name could not be blotted out, unless it was written there in the first place. This verse implies that we have to live a holy, blameless life. So, the true believer in Christ is one who does the commandments of God. Not just any believer.
Salvation appears to be a state of being.
WHO OBEY HIM, AND Repent and turn away from sin, to a life of righteousness. The most important thing - I rarely hear any Protaestant Preachers address this passage and realize what Jesus says in John 15. This is my commandment, that you love one another as I have loved you. So faith by itself, if it has no works, is dead.