This is something I've been wondering about too. Especially someone who lets say.. goes to church with their parents as kids and they accept Christ then and then when they get older like 20 or something, they "come to their senses" (in their mind) and figure that it's all not possible and it sounds like some kind of a fairy tail and they just don't really believe what they were taught as a kid (because kids are open to pretty much anything) So anyway, they just stop believing and say it's not real anymore. Would they lose their salvation then? and of course.. if later on in life something showed them the way that it was indeed all true and they started believing again then of course they would get their salvation back?
Or.. if someone accepted and then later started to rebel and called christianity stupid and everything and say it was all a big bunch of lies and made up stories and only really gullible people believed in that stuff, would they lose their salvation? and if they decided later that they were wrong about being "wrong" about it all, then get their salvation back after re-accepting Christ and be serious about it and change their ways? I believe yes.
But what if they don't? if they accept Christ and try to live a Christian life but as they get older decide it was all dumb and not ever turn back to Christianity, even tho they accepted and believed at one time, would they lose it they STOP believing called it all garbage and never believe again? What are your thoughts on that?
Whew!!! I'm getting dizzy...LOL!
This repeated "Seesaw" example of yours is, I am sure, not all that uncommon.
What it all boils down to is was the person in your questions really saved in the first place? A true "Born Again" Christian say would no, that going in and out of salvation is simply not scripture. On the other hand, there is plenty of truths in the Bible that your salvation is secure, like Jesus died once for all sins and God said he would never leave or forsake you as a couple of examples.
So, my thoughts are:
How many of your sins did Jesus die for? ALL!
How many times did he die for all of our sins? One.
How many times will he die again for these sins? None.
How do we know that he will die only one time for our sins? He said it was finished and he sat down at the right hand of God.
What did God say he gives us if we believe? The gift of salvation.
God does not give this gift, take it away, forgive, take it away, and so on. You can decide not to accept the gift but, once you do receive it, there is no such thing as you giving it back to God.
What does it mean when God says that he will look at our sins no more?
You will have an opportunity to ask him someday, but basically, when God looks at a True Christian, he calls him Holy, Righteous and Blameless, not because he sees the "Born Again" Christian, but because he sees His son who lives in the Christian. This process is called Justification: Gods gift of forgiveness and salvation, " Just as if we hadn't sinned"!
There is much more. God says if we seek him, he will seek us. Read his word daily seeking him and you will find your answers.