Can One’s Salvation Be Given Up?

Reformed by definition means to change something for the better. There are a lot of reformed denominations.

You either turn the other cheek or believe in self defense. It can’t be both.

Your salvation is at stake? Paul and Jesus called people fools.

Not resisting an evil person does not mean letting them beat you up.

I do not retaliate against those who do me wrong.

It's okay to call out a fool.
In fact, there's a whole book about that in the Bible.

What's not okay is to treat someone with contempt.

39 But I say unto you, That ye resist not evil: but whosoever shall smite thee on thy right cheek, turn to him the other also.

Sorry, this would make Christians the doormats of society.

The gospel of the kingdom did not concern eternal salvation, but a physical deliverance of Israel from their enemies with the restoration of the kingdom of Israel.

but whosoever shall say, Thou fool, shall be in danger of hell fire.

I see, so you meant reformed in a very generic way.

Yes, mid Acts dispensationlists do that. But of course, the term "better" is highly subjective, depending on how open one is.

What they do encourage is for people to read the Bible for themselves and interpret it based on what it literally says, as far as possible. You will be amazed how that results in many different church doctrine being revised.

How old are you?
Life's personal conflicts will teach you what it means to resist an evil person without laying a hand on them.
Hatred, defensiveness, vindictiveness, and revenge are our natural, fleshly ways we resist evil people. Jesus says don't do that. Remain vulnerable and do not be defensive or take revenge, in fact be kind to them. It really is the best thing to do. Drawing battle lines with those who resist and hate you only increases the intensity of the battle.

If someone hits my wife, I’m attacking in her defense. But in the kingdom, the Jews were instructed not to take matters into their own hands. The King and Judge is here.

There is no Gospel of the Kingdom. Will Israel always exist? Yes because God made a promise to the Israelites.

The disciples didn’t understand the death and resurrection of Christ? Huh...

Luke 18
31 Then he took unto him the twelve, and said unto them, Behold, we go up to Jerusalem, and all things that are written by the prophets concerning the Son of man shall be accomplished.
32 For he shall be delivered unto the Gentiles, and shall be mocked, and spitefully entreated, and spitted on:
33 And they shall scourge him, and put him to death: and the third day he shall rise again.
34 And they understood none of these things: and this saying was hid from them, neither knew they the things which were spoken.

The disciples thought the resurrection was an idle tale?

Luke 24
7 Saying, The Son of man must be delivered into the hands of sinful men, and be crucified, and the third day rise again.
8 And they remembered his words,
9 And returned from the sepulchre, and told all these things unto the eleven, and to all the rest.
10 It was Mary Magdalene and Joanna, and Mary the mother of James, and other women that were with them, which told these things unto the apostles.
11 And their words seemed to them as idle tales, and they believed them not.

Can you imagine a preacher today not knowing what the rising of the dead should mean?

Mark 9
9 And as they came down from the mountain, he charged them that they should tell no man what things they had seen, till the Son of man were risen from the dead.
10 And they kept that saying with themselves, questioning one with another what the rising from the dead should mean.

Should I continue?

So did Jesus only die for the Jews since he was crucified I Jerusalem?

Really?

Matthew 4:23 And Jesus went about all Galilee, teaching in their synagogues, and preaching the gospel of the kingdom, and healing all manner of sickness and all manner of disease among the people.

Matthew 9:35 And Jesus went about all the cities and villages, teaching in their synagogues, and preaching the gospel of the kingdom, and healing every sickness and every disease among the people.

Matthew 24:14 And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; and then shall the end come.

Of course not. But the gospel of the kingdom was only to Israel.

The term is 'raca'.
It's a word used to express contempt for a person, not a word used to point out the unwise (foolish) behavior of a person.

Yes really. You’re flatly misinterpreting due to your dispensational view.

What is the gospel of the kingdom? Please explain...

I can’t explain something that doesn’t exist.