Salvation isn't some title or office that can be walked away from like a bad job, nor is it the speaking of a few words at some point. It's a complete recreation of the individual, a sealing by the Holy Spirit, and the purchase of ourselves by another. there is no 'walking away' option. You are either saved and remaining, or never saved at all.
Scripture doesn't support that, however. First, the 'seal of the Holy Spirit' is not a seal that enforces us to remain in Christ. It's a legal term. The seal marks God's authority and guarantee that He will keep the future promises of the covenant at the judgement - it's not a rope that forces us to stay in the covenant. (For example, the seal on Jesus' tomb didn't physically increase the security of the tomb. Rather, it was the mark of Roman authority that anyone tampering with the tomb/body would be subject to death.)
"And in Him (in Christ) you were sealed with the promised Holy Spirit, having heard and believed the word of truth, the gospel of your salvation, who is the guarantee of our inheritance until we (those in Christ) acquire possession of it, to the praise of his glory." Eph 1:13-14
The seal doesn't make us be in Christ, nor does it make us remain in Christ. It's a guarantee that those in Christ will inherit the future promises such as new spiritual bodies, a place in God's kingdom, etc.) This passage itself and others on the seal of the Spirit shed no light on whether those who start in Christ can reject Christ later.
More here on this common misunderstanding of what the seal of the Holy Spirit means:
[Question: What is the seal of the Holy Spirit?
See Answer:
What is the seal of the Holy Spirit?]
Second, scripture does not show that either being redeemed or receiving new life in Christ means that that person cannot reject Christ and return to slavery to sin and the world. Here are just a few examples where the scripture is very clear that some can, and some do, just that:
Heb 6:1-6:
Heb 6:5-8 warns them of the case of Christians who had seen the light (
II Cor 4:6), ate of the heavenly gift (
John 6:33), shared in the Holy Spirit (
I Cor 12:13,
II Peter 1:4,
Eph 3:6,
Heb 3:14,
Col 1:12,
Phil 1:7,
Eph 4:4, etc), tasted the goodness of the word of God (
Psalm 38:4) shared in spiritual gifts (
1 Cor 12:4), and repented (
Acts 2:38), but
then fell away.
Clearly, some who have who partook in the Holy Spirit (literally, changed after sharing - something only Christians who have received the Spirit and resultant new life can do) have fallen away. There is no hypothetical about this falling away - the Greek is clear that they did fall away.
See also:
[Question: What exactly does "fall away" mean in Heb 6:6?
See Answer:
What exactly does "fall away" mean in Heb 6:6?]
Heb 10:23-29: Believers are warned to hold fast (a nautical term referencing to keep a ship's bearing) to their faith. This is contrasted with those in the passage who deliberately return to a state of sin (slavery to sin, not merely struggling with sin) and who treats as unholy the blood that formerly sanctified them and insults the Spirit of Grace.
This passage is opposed to the concept that it's impossible to reject the sanctifying blood or that the Spirit itself holds our course in faith fast.
See also:
[Question: What does the Hebrews 10:26 mean concerning 'willful sin?'
See Answer:
What does the Hebrews 10:26 mean concerning 'willful sin?'
Question: Does Hebrews 10:26 mean that a believer can lose salvation?
See Answer:
Does Hebrews 10:26 mean that a believer can lose salvation?]
John 15:1-6:
“I am the true vine, and my Father is the gardener.
He cuts off every branch in me that bears no fruit, while every branch that does bear fruit he prunes so that it will be even more fruitful...
.Remain in me,
as I also remain in you. No branch can bear fruit by itself; it must remain in the vine.
Neither can you bear fruit unless you remain in me. “I am the vine; you are the branches. If you remain in me and I in you, you will bear much fruit; apart from me you can do nothing.
If you do not remain in me, you are like a branch that is thrown away and withers; such branches are picked up, thrown into the fire and burned."
Here is a warning, strait from the mouth of Christ, that we must
remain in Him! That is to abide or stay - not merely sojourn temporarily. Those who do not remain will be cut off and burned! This is similar to the language of Rom
11:17-23 - we remain in the vine through faith, but if we do not continue in faith we will be cut off. As we see from
Jude 1:12, there were those who did not remain and bore no fruit - so they were uprooted and considered 'twice dead' - their former escape from the condemnation of death and former participation in the life-giving vine did not avail them.
II Pet 1:3-11 shows more in-depth how faith/remaining in Christ bears out in fruit, and how those without fruit are blind, unproductive in their relationship with Christ, and have 'forgotten' they were cleansed from past sins (not that they never had their sins forgiven or were never in Christ to begin with.)
There are many warnings in scripture about apostasy, turning back, making shipwreck of our faith (
I Tim 1:18-20,) etc. One of the clearest is
I Tim 4:1:
"The Spirit explicitly says that in later times some will depart from the faith and follow deceiving spirits and things taught by demons."
It's hard to get more explicit than something the Spirit explicitly says! Depart here in the Greek does mean to withdraw or leave from something you were once a part of. 'The faith' here is defined in the verses just before - that Jesus was seen by the world and believed in - so the interpretation that this verse must just mean a shallow profession of outward faith is a far harder meaning to pull from the text as there is no context to support it.
See also:
[Question: What does it mean in 1 Tim 4:1 that 'some will depart from faith, giving heed to deceiving spirits?'
See Answer:
What does it mean in 1 Tim 4:1 that 'some will depart from faith, giving heed to deceiving spirits?']
Luke 8:13
"Those on the rocky ground are the ones who receive the word with joy when they hear it, but they have no root.
They believe for a while, but in the time of testing they fall away."
This explanation of the parable of the sower, in Jesus' words, means that some people *can* believe (have faith) for a while but later fall away! There is nothing in the passage to restrict this to fake believing or mere head knowledge. They welcomed the word with ready reception and trusted in Christ. However, they did not stay rooted in Christ. They didn't abide in Christ so as to continually suck up nutrients from the root - so when hardship came they abandoned the faith and returned to the world.
II Pet 2:20-22
"For if,
having escaped the corruption of
the world by truly knowing our Lord and Savior
Jesus Christ and are again entangled in it and are overcome, they are worse off at the end than they were at the beginning.
It would have been better for them not to have truly known the way of righteousness, than to have truly known it and then to turn their backs on the sacred command that was passed on to them. Of them the proverbs are true: “A dog returns to its vomit,” and, “A sow that is washed returns to her wallowing in the mud.”
We see here former Christians - people who had escaped the corruption of the world! This first escape was only possible because they had true knowledge of Christ (not mere head knowledge) - the Greek word epignosis refers here to the relational/experiential knowledge Christians have with Christ, not mere book knowledge. They didn't just 'know about' Jesus and practice a few morals - they had a relationship with Christ which helped them escape the lusts of the flesh. But the, they returned to the corruption of the world! This latter state was worse than their former state of unbelief! After being washed and sanctified by the blood of Christ, they returned to washing in the mid of sin.
