Perseverence of the Saints

The problem however, is still that they believed.

The Scriptures are clear, "Believe on the Lord Jesus Christ and thou shalt be saved".

Obviously you know this but if we agree it is the gospel that is being believed and they believed then the promise of salvation applies and as it describes clearly they came to life, they simply did not take root.

Taking root is analogous to the growth process, not the birth process. Remember verse 6 in the Luke parable makes it clear that they "SPRUNG UP". They indeed did come to life and are treated as coming to life just as though who "SPRANG UP" but got choked. and those that "SPRANG UP" and bore mature fruit. All 3 are treated as coming to life through springing up (which is exactly what springing up is, coming to life).

1.Did not come to life.

2.Came to life, "SPRUNG UP" but did not progress beyond infancy.

3.Came to life, "SPRANG UP" came to life but did not grow beyond adolescence and bore no mature fruit (fruit to perfection).

4.Came to life, "SPRANG UP". Mature and Scripturally ideal believer.

This is not in dispute so I will just post the interpretation verse.

The one that withered, the one that got choked and the one that bore fruit are treaded identically (SPRINGING UP) regarding having come to life. The first is the only one that is treated as never coming to life lest they believe and be saved.

So if the 2nd one "SPRUNG UP" and the 3rd and 4th one "SPRANG UP" as did the 2nd one, you have a problem claiming two are believers with life and the other isn't when they are all three treated identically regarding their coming to life and only the 1st is treated otherwise.

Summation:

1. Never came to life. Did not believe and be saved.
2. "SPRUNG UP". Came to life but did not progress beyond spiritual infancy.
3. "SPRANG UP". Came to life but did not progress beyond spiritual adolescence (immature fruit).
4. "SPRANG UP" Came to life and bore mature fruit.

In the text why do they wither? No moisture. Meaning no life sustaining water that softens the soil and enables rooting to take place. Not taking in moisture (the water of the Word) is treated as unbelief. When one neglects taking in Bible doctrine to mature they are indeed acting in unbelief. Does this mean the very gospel they believed to be saved can also be denied? Yes, one can do that though the text is not necessarily requiring you to conclude that since again, "moisture" is analogous to taking in the Word after coming to life, i.e. "SPRUNG UP". Most valid is the few that their believing for a while and falling due to temptation is the post-salvational indoctrination that enables our faith to grow, hence the analogy of moisture. But can a person who has been saved as some point actually contend they no longer believe the gospel? Yes, of course.

Why?

Because when a man or woman believes the gospel, from that point onward it is the integrity of Christ that guarantees its promise of redemption, not man's attempt to maintain his faith. Should a person not deny the gospel, of course they shouldn't but the Bible documents believers who have fallen from their faith, even denying the Lord that bought them.

A volitionally accountable person cannot be saved if they have NEVER believed the Gospel and one who has believed the gospel is obviously saved. One might ask, can a person believe the gospel and then deny it (when I state "believe the gospel" that means saved. There is no in between in the Bible, either you believe or don't). The answer is yes, they can deny even the Lord that bought them. It is the Lord that will never leave us.

The Corinthians passage I believe isn't qualified to be used to interpret this parable, however. The contexts are not the same. Discovering what Paul is saying is worthwhile and I do not agree with your conclusion, but the parable itself is self-interpreting and qualified on its own.

But per this passage, Paul states in 1 Corinthians 15:

He is not talking about believing the truth in vain, he is talking about believing a corrupt gospel which WOULD be belief in vain. Remember, the issue is that they were saying the resurrection had not happened. The resurrection is part of the message and promise of redemption.

His point is that they are to "keep in memory what I preached unto you" which also included the RESURRECTION promise which was being denied.

His point isn't that they MIGHT believe and and not REALLY be saved as you are contending "believe in vain" means but that to deny the resurrection by default makes a person to have believed in vain since that is the ultimate purpose of redemption, our resurrection through Christ.