Can One’s Salvation Be Given Up?

Of course it's different. Paul never preached the gospel of the kingdom. Paul's gospel was called the gospel of the grace of God or the gospel of Jesus Christ.

The gospel of the kingdom was for the Jews only. Paul's gospel is for everyone. Why the difference? The Jews earthly kingdom is not to be preached to the Gentiles or Samaritans.

No, Paul made it clear that Abraham was justified apart from works. Before his circumcision. Before anything he did.
He's showing that's how it's always been. The covenant of law did not change that. It can't.
This is explained in Galatians.

Abraham believed God regarding the promise of a son who would inherit the blessing on his behalf, and was justified through his faith.
We also believe God regarding the promise of the Son who has inherited the blessing on our behalf, and are justified through that faith.
Same gospel. Same truth.
We just know more details about it than he did.
The gospel has always been about faith in God's promise of a son.

No, Paul makes that clear too.
The promise made to Abraham was that all nations would be blessed through him.
The gospel has always included the gentiles, right from the start.
Even under the law, the gentiles were allowed to be in covenant with God. (unconverted God fearing gentiles-Acts 17:4)
The inheritance of the kingdom is for them too. Always has been.
One and the same kingdom/ inheritance message.

Salvation by grace through faith cannot be given up, lost or walked away from. Man is not sovereign and is under the authority of Christ or sin at all times. Christ does not ever lose any that are His by grace. None are His by deeds of their own hands.

For the cause of Christ
Roger

Well, that's what Paul preached, so they did preach different messages. The gospel that Paul preached was specifically how Christ died for our sins, was buried and rose again the third day. This message is to all the world. The gospel of the kingdom was restricted to Jews only.

no its not restricted to jews. that racist doctrine is not true

Matthew 28:19-20 great commission go to all nations (not just one nation, israel). matthew 24 says this gospel of the kingdom shall be preached to all nations. you guys say its the angel who does this in tribulation or something whatever, still it says all nations not one nation israel.

Gospel of the kingdom was only for the Jews

Matthew 10
5 These twelve Jesus sent forth, and commanded them, saying, Go not into the way of the Gentiles, and into any city of the Samaritans enter ye not:
6 But go rather to the lost sheep of the house of Israel.
7 And as ye go, preach, saying, The kingdom of heaven is at hand.

no it wasnt. keep reading to matthew 28 where Jesus says go to all nations and preach what ive taught you. you are stuck in chapter 10

Thanks for posting. How would you interpret the verses that were provided?

Every one supports the doctrinal truth that salvation cannot be lost. Sanctification can be interrupted but salvation cannot be lost or given up. It's not ours but Christ's.

For the cause of Christ
Roger

So in your opinion they should be listed in the last part of the OT and the NT starting in the middle of Acts?

But still you haven't said what do you do with the red letter words of Jesus? Do you take Paul's letters more over the words of Jesus? Or are they equally important to the believer?

Still trying to understand. I'm not really seeing the importance here. What in your theology is supposed to change the beliefs of others theologians?

You sound like you are in a church that preach almost exclusively from the 4 Gospels, or you consider yourself a red letter Christian.

“If any man think himself to be a prophet, or spiritual, let him acknowledge that the things that I write unto you are the commandments of the Lord” (1 Cor. 14:37).

Paul's words to us are the words of the ascended Christ to us former gentiles. Christ Jesus saved Paul specifically to reach to us Gentiles. Acts 22:21.

Jesus words in red in the 4 gospels were directed to the Jews. You can learn a lot about a letter writer from the letters he wrote to other people but you don't read them as necessarily instructions to you.

As for your last paragraph, an example where you don't read his instructions to you are, for example, John 20:23. None of us now have the power to forgive sins or retain them. Another example would be Mark 16:16-18/Acts 2:38, we don't tell people they need to believe AND be baptized to be saved, neither do we tell believers to pick up serpents and drink poison as a sign that they believed.

Abraham was considered righteous when he believed God at His word, Genesis 15. His justification did not come until He sacrificed Isaac in Genesis 22.

James 2
21 Was not Abraham our father justified by works, when he had offered Isaac his son upon the altar?
22 Seest thou how faith wrought with his works, and by works was faith made perfect?
23 And the scripture was fulfilled which saith, Abraham believed God, and it was imputed unto him for righteousness: and he was called the Friend of God.

None of us now have the power to forgive sins or retain them.

In regard to this subject 'justified' has two distinct definitions.
This can be confirmed in any dictionary: https://www.dictionary.com/browse/justified

James is using 'justified' according to the 'to be shown to be righteous' definition.
Abraham's obedience showed him to be righteous in God's sight in Genesis 22. And so he was justified by what he did.
But he was made righteous by his faith way back in Genesis 15:5.

"...a son who is your own flesh and blood will be your heir.” 5He took him outside and said, “Look up at the sky and count the stars—if indeed you can count them.” Then he said to him, “So shall your offspring d be.”

6Abram believed the Lord, and he credited it to him as righteousness." - Genesis 15:4-5

Justification requires obedience. Abraham’s obedience to offer Isaac as a sacrifice justified his righteousness. He was declared righteous in chapter 15, but his justification was fulfilled in chapter 22.

James 2
22 Seest thou how faith wrought with his works, and by works was faith made perfect?
23 And the scripture was fulfilled which saith, Abraham believed God, and it was imputed unto him for righteousness: and he was called the Friend of God.
24 Ye see then how that by works a man is justified, and not by faith only.

10Anyone you forgive, I also forgive. And what I have forgiven—if there was anything to forgive—I have forgiven in the sight of Christ for your sake - 2 Corinthians 2:10

Another question that could be raised regarding the OP question, why would anyone want to give up their Salvation? Considering the alternative and all.

That’s a good question. I don’t think one answer could apply to everyone. I would attest that when someone turns back to a life of the flesh, their heart hardens against God desire for righteousness. Perhaps they are not even aware that they are bringing on condemnation. Maybe they just stop caring and continue in their transgressions without fear.

21 For the upright will live in the land,
and the blameless will remain in it;
22 but the wicked will be cut off from the land,
and the unfaithful will be torn from it.
Proverbs 2:21-22