OK, have you ever known anyone who has gone through this? I don't mean specifically Mormonism, but a person who you consider "truly reformed Presbyterian or reformed baptist" and left "the gospel" for some other religion?
Maybe I'm misunderstanding, but it seems as though you are assuming that you can recognize that a person is "truly reformed Presbyterian or reformed baptist", by which I think you mean "having true, saving faith". Is this correct?
Well, there are the "flash in the pan," sorts of people who come into our Church, look good for a few months, learn some of the lingo, and then pass right on out of the Church. Some of these people drift from Church to Church with some very different kinds of theology. None of them would deny that Jesus is Lord and savior, but I would have to get to know and be able to question some of these people to believe their confession is true faith.
I know some in protestant Churches who claim "I asked Jesus into my heart." They later fall away. Of course I would be quite skeptical of such confessions as understanding anything about the gospel. Some cling to the jargon "I was born again." While that is a little more biblical, I again would remain skeptical. This is not to say that if someone learns a certain jargon as Born Again, or "ask Jesus into your heart" is going to hell, but I would undoubtedly question the validity of their understanding of the gospel and consider the possibility that they are not saved.
Now there is a Orthodox Presbyterian Church nearby in which a young man grew to adulthood and wants to join the Roman Catholic Church and become a priest. I do not know a lot about this, but I heard the Roman Catholic Church rejected him for the priesthood and rejected him to attend a Roman Catholic Seminary. He went to Eastern Europe and teaches in some school. This guy's sister attends our Church, and so I never personally met him. He might make an interesting case study on those who leave reformed theology. I would be interested to see if he ever thought the gospel of Roman Catholicism is a false Gospel. Or did he always think of it as an option, a kind of true Gospel that had a few minor errors in it. This does not mean he is or is not truly saved, I would however, again, question his understanding of the gospel. What did he begin with? There would be a lot of questions I would like to ask this individual.
Another interesting case study might be the self proclaimed apostate Bart Erhman. I am aware he went to Moody Bible Institute, then went to Princeton, and is now a self-proclaimed agnostic and apostate. Moody Bible Institute is not a school of reformed theology. I doubt they would claim to be Reformed.
Really, Mondar I'm not trying to confuse the issue by mixing in what actually saves, whether that be baptism, faith alone, faith and works or whatever. All I'm saying is that James' point is that we can "show" to others that we have "saving faith", we can prove our faith (or claim of faith) is justified by our works and others can see it. You seem to agree with this, so moving on, IF we prove our faith is "true", then "leave the gospel", the only logical conclusion you could come to is that we can lose our faith. We have already "shown" we had "saving faith" by our actions, so if we "leave the gospel", "he was never saved in the first place" is a fallacious conclusion.
Be patient with me, I really do think it is very easy to talk past each other. For me, my understanding of "true faith," is that "true faith" is the only criteria for salvation. So the issues are identical for me from my perspective. From your perspective I think things are different. If more then true faith in the atonement of Jesus Christ is necessary for Salvation, then one can have "true faith" and still be unsaved because they have not yet met the other criteria for salvation.
Certainly I agree with the logic of your statement " IF we prove our faith is "true", then "leave the gospel", the only logical conclusion you could come to is that we can lose our faith." That of course is the question of all the anecdotal stories. The question I want to ask of those who "leave the gospel" is where were they really at the starting point. Remember, in my theology, the gospel is sola fide. If you add to sola fide, you change the nature of the Gospel.
Going back to the lad that left the OPC, and became Roman Catholic... did he move from the position of sola fide to one in which more than faith is necessary for justification? Or was he somewhere in the middle? Would he have said that both are acceptable?
Would Bart Erhman have agreed with sola fide as the gospel when he attended Moody? Did he even hear of the term at Moody?
I can see your point about apostasy if I do not think in terms of Reformed theology, but one of the problems with Reformed theology is that it is very finely and carefully defined. Most other protestants enjoy much more vagueness to their theology. There is the problem in a nut shell. When I try to peer into the past of many protestants and find this fog and vagueness, it is hard to tell what is truly apostate, and what is not.
If I saw someone that I thought was truly apostate from reformed theology, I would of course be very curious and interested. I would also have to ask, how can this be.