Is it really faith + IF = finally saved (prescriptive) or does IF confirm faith and conversion? (descriptive)
In Hebrews 3:14, we read - For we
have become [past tense Greek verb, gegonamen, meaning we have become already] partakers of Christ,
(demonstrative evidence) if we hold fast the beginning of our confidence steadfast to the end. Notice that this is essentially a repeat of verse 6, where we read: but Christ was faithful as a Son over His house -
whose house we are, (demonstrative evidence) if we hold fast our confidence and the boast of our hope firm until the end. The wording is not - "and you will become partakers of Christ (future indicative) if you (future indicative) hold fast the beginning of your confidence steadfast to the end." It is rather -
"you have been, and now are, partakers of Christ,
(demonstrative evidence) if in the future you hold fast the beginning of your confidence steadfast to the end. What about the faltering Hebrews who end up departing from God after beginning with self confidence and profession of loyalty, but then later?
Future perseverance is proof of genuine conversion.
IF, that is, continuance would show that the person's faith is firmly established in the hope of the gospel and they really HAVE BEEN reconciled. The form of this phrase in Greek indicates that Paul fully expects that the Colossian believers will continue in the faith; no doubt is expressed, yet what about "nominal" Christians who do not continue in the faith they originally professed? So IF confirms being grounded in hope of the gospel and authentic faith.
It makes sense that Paul would speak this way because he is addressing groups of people who "profess" to be Christians mixed in with genuine Christians, yet without being able to infallibly know the actual state of every person's heart. How can Paul avoid giving them false assurance of salvation when in fact they may not even be saved in the first place? Paul knows that faith which is firmly grounded and established in the gospel from the start will continue. Those who continue in the faith show thereby that they are genuine believers. But those who do not continue show that their spurious faith was not grounded in the gospel to begin with.
In John 15:2-6, the branches that
bear fruit and remain are genuine believers (like the remaining 11 disciples). The self-attached branches that
bear no fruit and do not remain are not genuine believers (like Judas Iscariot). In John 15:2, Jesus mentions branches that
bear no fruit and branches that
bear fruit but Jesus says nothing about branches that bear fruit but then later stop bearing fruit.
Greek scholar AT Robertson points out that there are
two kinds of connections with Christ as the vine (the merely cosmic which bears no fruit, the spiritual and vital which bears fruit). Probably (Bernard) Jesus here refers to Judas. -
https://www.biblestudytools.com/commentaries/robertsons-word-pictures/john/john-15.html
When Jesus spoke these words in John 15, how many people at that time,
prior to Him being glorified, had received the Holy Spirit and were baptized by one Spirit into one body? - "the body of Christ?" (1 Corinthians 12:13) -- NONE.
John 7:38 - He who believes in Me, as the Scripture has said, out of his heart will flow rivers of living water. 39 But this He spoke concerning the Spirit,
whom those believing in Him would receive; for the Holy Spirit was not yet given, because Jesus was not yet glorified. So "in me" is part of the metaphor of the vine (in the vine) and not in the body of Christ under the New Covenant which was not yet fully established.
Without that vital union with Christ, there can be no spiritual life and no good fruit. Those who merely profess to know Christ but whose relationship to Him is self-attached, Christ neither saved them, nor keeps/preserves them. Eventually, the dead self-attached fruitless branches are cut off.
Abiding is descriptive of genuine believers. 1 John 4:13 - By this
we know that we abide in Him, and He in us, because He has given us of His Spirit. 14 And we have seen and testify that the Father has sent the Son as Savior of the world. 15
Whoever confesses that Jesus is the Son of God, God abides in him, and he in God.