Hello Throughfaith!
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But if the wicked man turns from all the sins he has committed, keeps all My statutes, and does what is just and right, he will surely live; he will not die.
22None of the transgressions he has committed will be held against him. Because of the righteousness he has practiced, he will live.
23Do I take any pleasure in the death of the wicked? declares the Lord GOD. Wouldn’t I prefer that he turn from his ways and live?
24But if a righteous man turns from his righteousness and practices iniquity, committing the same abominations as the wicked, will he live? None of the righteous acts he did will be remembered. Because of the unfaithfulness and sin he has committed, he will die.
25Yet you say, ‘The way of the Lord is not just.’
Hear now, O house of Israel: Is it My way that is unjust? Is it not your ways that are unjust?
26If a righteous man turns from his righteousness and practices iniquity, he will die for this. He will die because of the iniquity he has committed.
27But if a wicked man turns from the wickedness he has committed and does what is just and right, he will save his life.
28Because he considered and turned from all the transgressions he had committed, he will surely live; he will not die. (Ezekiel 18:21-28)
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Also, salvation for those in Christ is dependent upon continuing in faith. If a believer turns from his faith (apostasy) and dies in that state, then that person will die in their sins.
We are saved by God's grace through faith and not by a one time confession of Christ, but by taking up our crosses daily. Therefore, if a believer turns back into the world and goes back to willfully lives according to the sinful nature, in that state he is accumulating sin and is on his way to condemnation, unless of course he repents and turns back. I gave you all of those scriptures, but here is another example:
"But suppose that servant is wicked and says in his heart, ‘My master will be away a long time.’ And he begins to beat his fellow servants and to eat and drink with drunkards. The master of that servant will come on a day he does not expect and at an hour he does not anticipate. Then he will cut him to pieces and assign him a place with the hypocrites, where there will be weeping and gnashing of teeth."
The above is an example of those who would stop having faith and no longer watching for the Lord and turning back to living according to the sinful nature, which is represented by (And he begins to beat his fellow servants and to eat and drink with drunkards.)
If we were just saved no matter what we did after we received Christ, what would be the purpose of all of the warnings throughout scripture, as well as the letters to the seven churches in Revelation? In those letters there are promises to those who overcome and eternal consequences for those who don't. And we can't say that they are not believers, because the letters are addressed to the church and the individuals within it.
Once saved, always saved, is true if one continues in faith to the end of their life or until the Lord comes to gather His church.
Once saved, always saved, is not true if one turns away from his faith and goes back into following the world and willfully living according to the sinful nature.