Yeah a person who believes has crossed from death to life and if they were to die while they still believe they would receive eternal life. But if that person falls to disbelief they lost their eternal life.
“My brethren, if any among you strays from the truth and one turns him back, let him know that he who turns a sinner from the error of his way will SAVE HIS SOUL FROM DEATH and will cover a multitude of sins.”
James 5:19-20 NASB1995
WOW Do ya see that? Bringing a person who once believed from unbelief back to belief again SAVES HIS SOUL FROM DEATH. Are you reading this? So apparently according to James here, someone who has passed from death to life CAN pass back from life to death. And not just a physical death but the death of their soul, that’s the second death FYI.
“For if we go on sinning willfully after receiving the knowledge of the truth, there no longer remains a sacrifice for sins, but a terrifying expectation of judgment and the fury of a fire which will consume the adversaries. Anyone who has set aside the Law of Moses dies without mercy on the testimony of two or three witnesses. How much severer punishment do you think he will deserve who has trampled under foot the Son of God, and has regarded as unclean the blood of the covenant by which he was sanctified, and has insulted the Spirit of grace? For we know Him who said, “Vengeance is Mine, I will repay.” And again, “The Lord will judge His people.” It is a terrifying thing to fall into the hands of the living God. But remember the former days, when, after being enlightened, you endured a great conflict of sufferings, partly by being made a public spectacle through reproaches and tribulations, and partly by becoming sharers with those who were so treated. For you showed sympathy to the prisoners and accepted joyfully the seizure of your property, knowing that you have for yourselves a better possession and a lasting one. Therefore, do not throw away your confidence, which has a great reward. For you have need of endurance, so that when you have done the will of God, you may receive what was promised. For yet in a very little while, He who is coming will come, and will not delay. But My righteous one shall live by faith; And if he shrinks back, My soul has no pleasure in him. But we are not of those who shrink back to destruction, but of those who have faith to the preserving of the soul.”
Hebrews 10:26-39 NASB1995
For when you have done the will of God YOU MAY RECEIVE WHAT WAS PROMISED.
“For if, after they have escaped the defilements of the world by the knowledge of the Lord and Savior Jesus Christ, they are again entangled in them and are overcome, the last state has become worse for them than the first. For it would be better for them not to have known the way of righteousness, than having known it, to turn away from the holy commandment handed on to them. It has happened to them according to the true proverb, “A dog returns to its own vomit,” and, “A sow, after washing, returns to wallowing in the mire.””
2 Peter 2:20-22 NASB1995
For those who fall away from the faith their fate is WORSE than before they believed.
This is basic Sunday school 101 that my 9 year old daughter already knows. If a person believes, they’re saved, if they stop believing they’re not saved anymore.