The word “works” to the modern-day church is like a cuss word. They hate to hear it and equate it to false doctrine! The Bible, on the other hand, says much good about it, especially in James. James was clear in stating a saving faith in Jesus will have [good] works with it (James 2:14-17). If there are no [good] works then it is not a saving faith and merely the faith of demons.
Works (obedience) is the proof of a saving-living faith, but one is still saved instantly at the point of a trusting-submitting faith in Jesus, even before any good works are seen by man. An example is the dying thief, who repented:
Then he said, “Jesus, remember me when you come into your kingdom.” Jesus answered him, “I tell you the truth, today you will be with me in paradise.” (Luke 23:42,43)
His sincere and humble prayer to JESUS for mercy brought justification even before man could see any good works, which in that case were never seen because he died soon afterwards. Other examples of instant justification before works are seen by man are found in Luke 7:50; Acts 10:34-43; etc.
But someone will say, "You have faith; I have deeds." Show me your faith without deeds, and I WILL SHOW YOU MY FAITH by what I do. (James 2:18)James is saying others can identify a saving faith in the Lord Jesus by what one does. His actions and words reflect his heart, but that does change we are saved by a submissive obedient faith in Jesus.
James cites Abraham to make a similar point about this. The reason this seems confusing is because James is talking about, at one point, being justified by works before man. James clearly stated in 2:23 that Abraham became righteous when he believed God. That occurred at Gen 15:6. It wasn't until Gen 17:23-27 that Abraham was circumcised and it wasn't until Gen 22 that he offered up Isaac as a sacrifice. James wrote the following. Note especially verses 21 and 23:
You foolish man, do you want evidence that faith without deeds is useless? Was not our ancestor Abraham considered righteous for what he did when he offered his son Isaac on the altar? You see that his faith and his actions were working together, and his faith was made complete by what he did. And the scripture was fulfilled that says, “Abraham believed God, and it was credited to him as righteousness,” and he was called God's friend. You see that a person is justified by what he does and not by faith alone. (Jam 2:20-24)
If, in fact, Abraham was justified by works, he had something to boast about—but not before God. What does the Scripture say? “Abraham believed God, and it was credited to him as righteousness.” (Rom 4:2-3)
... Is this blessedness only for the circumcised, or also for the uncircumcised? We have been saying that Abraham's faith was credited to him as righteousness. Under what circumstances was it credited? Was it after he was circumcised, or before? It was not after, but before! And he received the sign of circumcision, a seal of the righteousness that he had by faith while he was still uncircumcised. So then, he is the father of all who believe but have not been circumcised, in order that righteousness might be credited to them. (Rom 4:9-11)
Paul said Abraham was justified before works (circumcision in Gen 17) at the point of his faith (Gen 15:6). James is in agreement. James 2:24 is talking about man knowing another has a saving faith. James stated man could tell Abraham was justified when he offered Isaac (Gen 22), but he believed at Gen 15:6. Remember, we prove our repentance by our deeds:
... I preached that they should repent and turn to God and prove their repentance by their deeds. (Acts 26:20)
We prove our repentance before man by our deeds, but we are still saved [instantly] at the point of a trusting-submitting faith in Jesus. That is similar to what John wrote:
This is how we know who the children of God are and who the children of the devil are: Anyone who does not do what is right is not a child of God; nor is anyone who does not love his brother. (1 John 3:10)
While that is true, so are the following:
You are all sons of God through faith in Christ Jesus. (Gal 3:26)
All the prophets testify about him that everyone who believes in him [JESUS] receives forgiveness of sins through his name. (Acts 10:43)
He made no distinction between us and them, for he purified their hearts by faith. (Acts 15:9)
...Those who have DONE GOOD WILL RISE TO LIVE, and those who have DONE EVIL will rise to be condemned. (John 5:29)
Whoever BELIEVES IN HIM IS NOT CONDEMNED, but whoever does not believe STANDS CONDEMNED ALREADY because he has not believed in the name of God's one and only Son. (John 3:18)
**Together those two verses from the Lord Jesus teach: The one who "believes in" Jesus is not condemned (3:18), which is a present tense faith in JESUS that does good (5:29). Hence, our FAITH (belief) IS IN JESUS for salvation, the only Savior, not our many good deeds, which a saved person does.
Not everyone who says to me, 'Lord, Lord,' will enter the kingdom of heaven, but only he who DOES THE WILL of my Father who is in heaven. (Mat 7:21)
Remember also Heb 3:14 and Heb. 12:14:
We have come to share in Christ if we hold firmly till the end the confidence we had at first.
Make every effort to live in peace with all men and to be holy; without holiness no one will see the Lord.
Regarding what happens after instant justification, please know that saving-living faith in Jesus can die, cease to exist and be destroyed. Hence, you must guard yourself and hold on to what you have spiritually or you will lose it.
No doubt we are in a deep dark apostasy. Sadly, it is going to get worse to pave the way for the mark of the beast. We must learn to stand alone and be willing to die for the cause of Christ, if necessary. Remember:
They overcame him by the blood of the Lamb and by the word of their testimony; they did not love their lives so much as to shrink from death. (Rev 12:11)