Jn 5:24
Truly, truly, I say to you, he who hears my word and believes him who sent me, has eternal life; he does not come into judgment, but has passed from death to life. rsv
A person is first saved when he repents of his sins and believes in God. But merely believing that there is a God does not continue to save him. Obedience to God's commandments is what continues to save him.
Rom 10:9-10
because, if you confess with your lips that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved. 10 For man believes with his heart and so is justified, and he confesses with his lips and so is saved. rsv
A person is first saved when he repents of his sins and believes that God raised Jesus from the dead. But, mere lip service does not keep anyone saved. Obedience to God's commandments is what continues to save him.
Acts 16:31
And they said, “Believe in the Lord Jesus, and you will be saved, you and your household.” rsv
When a person first believes that Jesus will save him and he repents of his sins, Jesus will save him. But, this salvation will not continue unless He obeys God's commandments.
Repenting, believing and becoming baptized is what first saves us. But, unless we continue to be saved through obedience to God's commandments, and are still saved by our obedience to God's commandments at the time of death, we will not be approved to enter/inherit eternal life. Mark 16:16,
Acts 2:38, Acts 3:19
1 John 2:4
He who says “I know him” but disobeys his commandments is a liar, and the truth is not in him; rsv
The works of the law of Moses save no one.
The works of the law of Jesus do continue to save us.
James 2:20-26
Do you want to be shown, you shallow man, that faith apart from works is barren? 21 Was not Abraham our father justified by works, when he offered his son Isaac upon the altar? 22 You see that faith was active along with his works, and faith was completed by works, 23 and the scripture was fulfilled which says, “Abraham believed God, and it was reckoned to him as righteousness”; and he was called the friend of God. 24 You see that a man is justified by works and not by faith alone. 25 And in the same way was not also Rahab the harlot justified by works when she received the messengers and sent them out another way? 26 For as the body apart from the spirit is dead, so faith apart from works is dead. rsv
My point is that the good works once done by a righteous Christian do not keep him saved when he later deliberately chooses to sin.
Concerning the spiritual life and spiritual death of a soul:
Ezekiel 33:11-20
Say to them, As I live, says the Lord God, I have no pleasure in the death of the wicked, but that the wicked turn from his way and live; turn back, turn back from your evil ways; for why will you die, O house of Israel? 12 And you, son of man, say to your people, The righteousness of the righteous shall not deliver him when he transgresses; and as for the wickedness of the wicked, he shall not fall by it when he turns from his wickedness; and the righteous shall not be able to live by his righteousness when he sins. 13 Though I say to the righteous that he shall surely live, yet if he trusts in his righteousness and commits iniquity, none of his righteous deeds shall be remembered; but in the iniquity that he has committed he shall die. 14 Again, though I say to the wicked, ‘You shall surely die,’ yet if he turns from his sin and does what is lawful and right, 15 if the wicked restores the pledge, gives back what he has taken by robbery, and walks in the statutes of life, committing no iniquity; he shall surely live, he shall not die. 16 None of the sins that he has committed shall be remembered against him; he has done what is lawful and right, he shall surely live.
17 “Yet your people say, ‘The way of the Lord is not just’; when it is their own way that is not just. 18 When the righteous turns from his righteousness, and commits iniquity, he shall die for it. 19 And when the wicked turns from his wickedness, and does what is lawful and right, he shall live by it. 20 Yet you say, ‘The way of the Lord is not just.’ O house of Israel, I will judge each of you according to his ways.” rsv
Hebrews 10:26-30
6 For if we sin deliberately after receiving the knowledge of the truth, there no longer remains a sacrifice for sins, 27 but a fearful prospect of judgment, and a fury of fire which will consume the adversaries. 28 ,,,,,,,29 How much worse punishment do you think will be deserved by the man who has spurned the Son of God, and profaned the blood of the covenant by which he was sanctified, and outraged the Spirit of grace? 30 For we know him who said, “Vengeance is mine, I will repay.” And again, “The Lord will judge his people.”
A person who does not do good works will not be approved to inherit eternal life. You will know who Jesus' sheep are by their good works/fruits.
Matthew 7:19-24
Every tree (person) that does not bear good fruit is cut down and thrown into the fire (of hell). 20 Thus you will know them by their fruits.
21 “Not every one who says to me, ‘Lord, Lord,’ shall enter the kingdom of heaven, but he who does the will of my Father who is in heaven. 22 On that day many will say to me, ‘Lord, Lord, did we not prophesy in your name, and cast out demons in your name, and do many mighty works in your name?’ 23 And then will I declare to them, ‘I never knew you; depart from me, you evildoers.’
24 “Every one then who hears these words of mine and does them will be like a wise man who built his house upon the rock; rsv
Ephesians 2:8-10
For by grace you have been saved through faith; and this is not your own doing, it is the gift of God— 9 not because of works, lest any man should boast. 10 For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them.
First Jesus saves us as His gift to us. We can do nothing to merit this gift of salvation.
However, to be approved to inherit/enter eternal life after we die, we must continue in our salvation until we die. We continue in our salvation by doing the good works that God prepared for us to do and by obeying His commandments until we die.
This also applies to us today. If we deny God/Christ by doing evil works, we will not be approved to inherit/enter eternal life.
Titus 1:16
They profess to know God, but in works they deny Him, being abominable, disobedient, and disqualified for every good work. nkjv
Mark 7:6
He answered and said to them, “Well did Isaiah prophesy of you hypocrites, as it is written: ‘This people honors Me with their lips, But their heart is far from Me. nkjv
1 Timothy 5:8
If any one (Christian) does not provide for his relatives, and especially for his own family, he has disowned the faith and is worse than an unbeliever.
Matthew 13:20-21
As for what was sown on rocky ground, this is he who hears the word and immediately receives it with joy; 21 yet he has no root in himself, but endures for a while, and when tribulation or persecution arises on account of the word, immediately he falls away. rsv