I'm not even sure where to start. Salvation as understood in Orthodoxy differs so greatly from Protestantism and even much of Westernized Catholicism (as I've understood it) that we need entirely different definitions.
The Baptist tradition I grew up in taught that anyone old enough to understand the gospel who had been presented it was faced with two simple options: accept Jesus as God and savior and be saved or reject him and be lost. Saved people go to heaven, lost people go to hell, and once you are saved you can always be assured of your salvation. We are able to be saved because Jesus's sacrifice satisfies God the Father's perfect sense of justice, covering our sins and atoning our guilt. Other Protestant positions are similar, with more or less emphasis on belief vs. actions and some disagreement on the whole "once saved always saved" issue.
Needless to say, I believe there are some problems in this theology. I'll try to state them charitably. :) For starters, I don't think anyone is ever capable of understanding salvation. If we could analyze it, understand it, and break it down into a formula of actions so that--by our own will--we can fulfill a set of requirements to create salvation within us, then it isn't really a process of grace, is it?
Secondly, the conflation of the words faith and belief has led many to think that salvation is simply a matter of confessing belief, i.e. the sinner's prayer. This leads to the born-again mentality that can be summed up with lyrics like "I once was lost and now I'm found," casual admissions like "Of course I'm saved, aren't you?," and ecstatic exclamations such as "I found Christ!" Oh really? The eternally-begotten, son-like hypostasis of the ultimate root of reality by whom, for whom, and in whom everything in (and probably out of) the universe is created and maintained? You just...found that, did you?
The clencher, though, lies at the very foundation of the idea of salvation as it has come to be understood by the rationalist, legalistic West: substitutionary atonement. Simply put, God is upset with us, he can't stop being upset until a price is paid for our sinfulness, and that price was himself/his son in the form of a law-fulfilling, sin-covering blood sacrifice. Sorry, but I can't buy that. I've never been able to buy that from the moment I figured out what it meant.
I'm sorry my babbling has been pretty negative so far, but I think it is necessary to clarify what I'm not talking about before I can move on to what I am. Orthodoxy is full of this, and we call it apophatic theology. Especially when it comes to God, it is much easier to say what he isn't than than what he is. And even when we do say what he is in phrases like "God is love," we have to add the apophatic addendum, "but nothing like the love we are capable of understanding." So, I've probably ruffled some feathers talking about what I think salvation isn't, so now I'll fail miserably to make a botched attempt at explaining what it is.
I take that back. One more apophatic statement. :) His Grace, Bishop ALEXANDER, Auxiliary Bishop for the Diocese of Ottawa, Eastern Canada and Upstate New York delivered a sermon at our cathedral a few weeks ago about salvation. I was stuck out of the nave taking care of a grumbly baby, but Kerry told me about it. He told a story of Jehovah's Witnesses coming to his door and asking him the standard, "Are you saved by our lord and savior Jesus Christ?" His answer? "Yes. Possibly." I don't think an Orthodox Christian would ever use the word "saved" in the past tense in reference to anyone other than a canonized saint, because salvation is not a moment in time that can be pinned down and put in a frame.
So what is it? Now I have to be careful. Salvation is (read: might be according to the uneducated catechumen) the ultimate redemption of all matter brought about by God himself becoming incarnate in essence within the reality he sustains, living and dying in the flesh in order to illuminate life and conquer death. He simultaneously created and showed us the way to be deified. To borrow a popular phrase, God became man that man might become God (not in essence obviously, but like him).
So what is it for us? For me? First, it must be understood that Orthodoxy understands all of reality as being constantly sustained by God's energies. Even though creation is capable of bringing forth things out of itself and we are capable of exercising our own free will, nothing moves without God's energies moving it. Everything that happens, therefore, is either willed or allowed by God. Our job is to cooperate. God's grace is always bestowed upon us, but when we accept it and work with it in synergia, we enter a salvific state of theosis--becoming more 'one-with-God.'
What is that collaboration? I think it is somewhat of a mystery. It is different things for different people. For pre-Christian Israel, it was probably following the law. For pagans, it is probably exemplifying every aspect of their traditions that are pleasing to God. For atheists (thank God for atheists!), it is probably through the acts of kindness, benevolence, and Christ-like compassion they pour forth out of nothing but the goodness of their hearts. For the mentally ill, God alone knows what is salvific.
The spirit blows where it wills, and God is not a tame lion. I, personally, don't think there is any limit to Christ's ability to save and deify people, even those who consciously reject him.
For those of us blessed with the gospels, we have the commandments given by Christ himself--love God with all that you are and love every other human being just as you love yourself--as well as the rest of his recorded life to emulate. Perfect salvation is egolessness: consciously doing every thing we ever do in a spirit of love, thankfulness, and praise toward God and for the service of others rather than ourselves. It is doing this every waking and sleeping moment, and doing it joyfully (I love how Fr. Thomas Hopko says you can't be a Christian and not be joyful). That perfect salvation is heaven, if only it could be attained on this Earth.
But we're not perfect. We're broken. None of us is ever always a Christian. I succumb to pride, anger, pleasure, passion, and lose my conscious awareness of God--and with it my spirit of repentance--hundreds of times a day. Does that mean I lose my salvation? I don't think so. Again, if it were totally dependent on me, it wouldn't be grace and I'd have little to be thankful for other than God providing me with a really hard checklist (and a run-away brain). I can either be in or out of synergia with God to varying degrees, but I don't think that means that one moment I'm "saved" and anotherI'm not. At the end of all things, according to scripture, I'll be judged by a God who is outside of and greater than time--who sees my life not as an unfolding story of moments, but who always has seen, is seeing, and always will see the entire thing that I am, from birth on, as one contiguous line all at once. I hope I make a pleasing line.
So yeah. Salvation is a grace-filled mystery. It's something Christ does, not me. I'm trying to cooperate with him. I'll leave it at that.