Can One’s Salvation Be Given Up?

Neither does the Bible.
Mark 16:18 doesn't mean you can go around purposely picking up deadly snakes.
Here's what it means:

3Paul gathered a pile of brushwood and, as he put it on the fire, a viper, driven out by the heat, fastened itself on his hand. 4When the islanders saw the snake hanging from his hand, they said to each other, “This man must be a murderer; for though he escaped from the sea, the goddess Justice has not allowed him to live.” 5But Paul shook the snake off into the fire and suffered no ill effects. - Acts 28:3-5

Again, you keep forgetting that Paul was the harbinger of a new gospel, the gospel of grace, with different instructions.

Don't try to use the gospel of grace to understand the Gospel of the kingdom, which Mark 16:16-18 was under. The latter had signs and wonders to autheticate the message (John 20:30-31), take a look at the ending of Mark

20 And they went forth, and preached every where, the Lord working with them, and confirming the word with signs following. Amen.

Under the gospel of grace, we don't believe like the Jews, who required signs and wonders, we believe in faith.

Can we then say all people who backslide have hearts hardened toward God? When God sent the second Adam to deliver the new covenant that would heal the separation between God and fallen humanity, knowing the Good News words that would lead the thirsty and the tired to find sustenance in those words, do we then think God would not foresee the world's temptations leading some of us off the path?
When before there was a chasm between our race, the human race, and the Godhead, now the new covenant has joined us together again as God's word, a written invitation to renew ourselves and our hearts and rather than remain born to sin as the rule of this world, become reborn to glory as is the irrevocable eternal grace filled gift of our Creator. And after generations of heart break and loss for a people mired in this world and yet seeking something better for themselves, and for which the Good News resonates its invitation to come and sup with the King and be nourished in glory.

Would after all that span of generations of loss God not know some would have doubts, be afraid, feel unworthy still, and leave the way? I would say, of course He would.
After all God planned and did to renew the relationship between our race and the Father, would God let us go as easily as that when we are His now? Or would He foresee it all and as a consequence deliver the parable of the Prodigal, so that we might glean understanding from that tale. That while we may feel we are the son or daughter of the most High, that we can leave the path and venture into the world and squander our lives away there, (the Bible prodigals inheritance). And yet, the warning in that parable is, eventually we burn out, we are broken, and shall find the world that welcomed our riches, casts us into the mire with the swine when we have nothing more to give of ourselves for its sustenance.
The world is carnal and material and wants satisfaction and to gorge itself on the lives of men. And when the man is nothing more than flesh and bone, with nothing left to feast upon, the world buries them in the mud and moves on.

But that one that drags themselves out of that mire, humbles themselves to their condition, and has the will and strength to return home finds themselves welcome with open arms. Even when they have nothing to their name.
When the angels glory at the redemption , Salvation of a new soul here on earth, imagine how they celebrate when the prodigal returns to the fold.
God did so much to insure whosoever believes shall be saved, and never cast out. Being He knows all things, would He give up on us, because we gave up on Him?
When God made His eternal promise of immortal life through His free irrevocable gift, are we to think His knowing all things would have done that, made us new creations , filled us with His Holy Spirit, if He would leave us because we left Him?
Even Jesus knew Judas would betray Him to his enemies in the temple. And still, Jesus told Judas to go and do what he must do.

All that God tells you about how He will never leave you and no one will take you from His hand when you are His, is bond. Is a sealed promise, a covenant between you and the greatest creative power in existence.
Maybe we feel unworthy of that much love, since who knows ourselves better than we and our Creator? And maybe that's why we think if we do the wrong thing we'll lose everything Jesus died to give us.

Let go and let God. And trust that when your Creator knew you *the impersonal you reference, as in all Christians*, were worth dying for, that you should trust that is true and relax in the security God guarantees with His word.

Blessings.

No I'm from a church that reads the whole Bible. Of course there is context for every verse including Jesus. The Bible doesn't just speak to the people of the day but speaks across centuries. If you ignore the words of Jesus and only take Pauls then yes that isn't the norm for a Christian.

So do you follow what Jesus said in John 20:23 and Mark 16:17-18?

Do you take those instructions as being directed to YOU? Is that the norm for other Christians as well?

I'm not sure what else you are trying to prove. We read everything in context as I keep saying. John 20:23 is in context Jesus giving the disciples sole power to forgive.

Mark 16:17-18 is part of a added portion. The earliest manuscripts and some other ancient witnesses do not have verses 9–20. I personally from textual criticism and fluidity do not consider the end of Ch 16 to be true. But even if it was true it says some believers. That isnt a command. Paul miraculously survived a poisonous snake bite. We have testimonials from missionaries where miracles have occurred dealing with snakes.

You forget God is of supernatural power. Beyond the natural. A miracle is something beyond natural that occurs. Literally nothing is impossible in God.

None of this dictates to me as not important or less important than Paul's writings. John 20 provides me with more detail on how the Spirit was at work within the early church.

I am merely trying to show that almost no Christian really follow EVERYTHING Jesus said in the 4 gospels. They are very well aware that certain instructions he gave are not applicable to them.

As you have said correctly about John 20:23, it is only directed to the original apostles. It is not for YOU to claim for your own. As for that Mark passage, since you rely on the "oh not all the original manuscripts contain that passage so I can safely ignore that", that proves my point too.

Okay that is even in Paul's writings. He also had his own opinions and certain parts where he was only speaking to certain individuals like telling Timothy to drink wine. Or the letters themselves was to individual churches or people but yet we read them as they are also speaking to us a message.

Everything is important in scripture. Paul telling Timothy to drink wine for a stomach problem wasnt Paul speaking to me but it is important because 1 it shows some insight on the whole concept of alchohol vs drunkenness. It also shows that medical uses of natural products is also Biblical. It also tells me that not every medical ailment is of spiritual attack.

And no I rely on evidence to tell me that the end of of certain Mark translations are not accurate. You can debate me otherwise but for none of the early translations to have it is quite obvious. It doesn't even match the fluidity. It does not prove your point. As said even if it was true it wasn't a command but only a prophetic message saying some will do those things.

Question: How do you view this passage?

This, then, is how you should pray:

“‘Our Father in heaven,
hallowed be your name,
10 your kingdom come,
your will be done,
on earth as it is in heaven.
11 Give us today our daily bread.
12 And forgive us our debts,
as we also have forgiven our debtors.
13 And lead us not into temptation,
but deliver us from the evil one.

As I said, you do agree that some of Jesus's instructions in the 4 Gospels are not applicable to us. I don't know why you don't want to admit this.

As for your question on the Lord's prayer, obviously verse 12 is not for us today. God does not forgive us our sins based on whether we forgive others or not.

As for vs 10, if you hold on to the distinction between the gospel of the kingdom and the gospel of grace, prophecy vs mystery, it is also inapplicable today. We gentiles are included in the salvation plan precisely because the Jewish nation rejected their king and their kingdom.

That kingdom offer is now postponed until the church is raptured before the Great Tribulation. In the current grace dispensation, we do not pray for the kingdom to come, that prayer is only applicable until the stoning of Stephen.

What do you mean I have agreed with you on the context. But all scripture is useful for teaching and instruction. So all is important.

That isnt the purpose of verse 12. That is a simple part of prayer. How long have you been a Christian? Or better yet how long have you studied the Word?

Verse 10 definitely is still applicable. There is a Earthly Kingdom to come and Heaven is very often called a Kingdom.

Agree Gentiles was prophetically given salvation as Israel rejected their Messiah.

Nope it is on the way and has been planned since before time. God who is outside of time saw the beginning and end and has everything planned from the start. Nothing wrong with praying for God's Kingdom to come which is a prophetic promise. Prophecy involves both natural and supernatural. Their will be a Earthly Kingdom just as there is a Heavenly Kingdom.

This is becoming like debating a Mormon. They use the same words and promote same scriptures yet when defined or explained the words are defined differently and scripture is twisted.

It's like I can agree to a point and then your paragraph just takes a nosedive. Like it starts in truth but then gets ugly.

Jesus explained what he meant in vs 12 later on when he stated

Matthew 6: 14-15 "For if you forgive other people when they sin against you, your heavenly Father will also forgive you. But if you do not forgive others their sins, your Father will not forgive your sins.

Are you still unconvinced that vs 12 does not apply under the grace covenant? Under grace, we forgive because we have already been forgiven. Ephesians 4:32

As for your disagreement over the kingdom, well, we can agree to disagree since people will need some time before they understand the distinction between prophecy and mystery.

Boy, I can't even remember all the people that have sinned against me. I guess I'm in danger of hell.

Yes, heaven is a place. We live in the first heaven. The earthly kingdom has been promised to Israel with their rightful King on the throne of David ruling from Jerusalem. The King will deliver Israel from their enemies so they can worship God without fear.

When you say people then you must come into a lot of opposition to your theology which is a good sign that something may be wrong with your interpretations.

Let me ask you. Would you be right to go and live a unforgiving state of mind? Would that indicate a fruit of saved individual? Wouldn't you agree there is something to learn here? And again Jesus was teaching a lot from the law which is perfect and holy. His main purpose was to show we cannot save ourselves. Even if we could forgive everyone, at some point during Jesus's teachings we would see ourselves as a sinner. A Sinner. That is the point. Even forgiving all the time is hard. That is the point. Jesus basically showing the law sets the bar higher than we could ever achieve on our own.

This is just simple Christian doctrine.

If I recall that will take place during the 1000 year reign. Correct?

That's the fault of the weak seminaries who are producing these pastors who do not know how to rightly divide the word of truth, especially Israel from the Church.

that is the exact reaction Jesus was hoping to stir up in the Jews who was trying to uphold the law. And us today if we are trying to be perfect.

Absolutely! That's not Church doctrine, but for Israel. The Lord will bring His bride back to reign on the earth with Him, but the promises of the kingdom is to Israel. You receive kingdom living as a Jew in the four gospels as the Lord is preparing them for this kingdom. Unfortunately for Israel, they rejected their King and this kingdom has been put on hold. The Church is a mystery in Scripture and may have never taken place if not for Israel's rejection.

Thankfully, I don't have that requirement.

The seminarrmies are half the problem. They usually create skeptics with all the theologies they push on people.

Dont even know why we put so much weight on degrees. God's word can use anyone not just super scholarly Pastors. It is often the basic Gospel that people have enough energy to pay attention to. Study groups are designed for the weightier stuff.