Which Americans who enter the tribulation will survive it? Which ones will become part of the first generation of Israel to live in the millennium?
God will decide.
Bible prophecy indicates one third of Israel will die in the famine and disease, one third will die in war, and one third will be captured by their enemies and go into captivity, and most of them will die in captivity. Only about ten percent will survive (Ezekiel 5:1-4, 11-12, Amos 5:1-3). I do not know if the ten percent is ten percent of all Israel before the tribulation or ten percent of the one third that goes into captivity (which would be about 3% of the total pre-tribulation population).
God will decide who survives the captivity.
There will be a purging of those who are the most rebellious. "I will make you pass under the rod, and I will bring you into the bond of the covenant; I will purge the rebels from among you, and those who transgress against Me; I will bring them out of the country where they dwell, but they shall not enter the land of Israel. Then you will know that I am the LORD" (Ezekiel 20:37-38).
It may be that the warning message we give before the tribulation begins will be part of a testing process God uses to determine who He will keep alive to be the first generation of Israel in the millennium.
That first generation will be important. God is going to use Israel as a model nation to illustrate to the world the right way of life (Deuteronomy 4:5-6). Conversion will start with Israel and spread outwards. The capital of Israel, Jerusalem, will also be the capital of God's government over the earth (Isaiah 2:3).
It is important to God that He purge the most rebellious elements from that first generation.
How people react to our warning message can be a test. Even among people who are not called to salvation in this age, reactions to a warning message can vary. Some will react strongly against it and against us in the Church who deliver that message. Some will become angry and will hate us and persecute us. Some will laugh us to scorn. They will deride the warning, make fun of it, twist it, and attack it.
But not everyone. Some may be sorrowful to a degree. Some may be afraid. Some my try, in their human way, to respond. Even among those who are against the warning, some will be less intense than others. God can judge each person's heart by how he or she reacts to our warning message.
There is going to be a testing and a judging and a selection that goes on to determine who will be part of that first generation of Israel that will be the model nation in the millennium. This testing and judging can occur all through the tribulation, but it can start from the time a person hears the warning message. People's actions and reactions to our message will help to show God who is acting most rebelliously and who is not.
As God tested Abraham by giving him a message to see his reaction (Genesis 22:1-2), as God tested Saul by giving him a command to obey (1 Samuel 15:1-3), so God can test all Israel by the message the Church of God delivers to each one of them. As each person hears our message and reacts, that person shows God his heart.
Everyone who hears the warning message must make a choice. When we tell the people, God is bringing punishment on you and this whole nation because of your sins and here is the proof in the Bible, each person will react in his or her own heart one way or another. They will react also with their words, one to another, as they talk about it, and they will react with their behavior, or lack of it. By all these things, God can judge who are the "rebels" he talks about in Ezekiel 20:37-38. God will see to what degree a person may be teachable in the millennium and to what degree that person is inclined to resist the truth.
Can an uncalled person respond positively to the warning? God is only calling a few in this age. Satan deceives the rest in this age. Unless God grants the gift of repentance and opens a person's mind and draws him or her to Christ, that person cannot be converted in this age.
But it is a mistake to think that the uncalled masses have no free will, no free moral agency, no choice at all, no responsibility for what they do. While they cannot repent with the depth of repentance God requires for conversion unless God gives that repentance as a gift, they nevertheless do have some free choice. They all don't have to try to kill us. They all don't have to totally ignore the warning, making no effort at all to change.
Perhaps some, out of fear of consequences, not with a depth of repentance and faith God requires for conversion, but trying to avoid the coming punishment, will make some effort to change. They may be a little bit afraid. They may say, "What if it's true?" That is not enough for conversion in this age, but it is at least a better reaction than, "Let's kill those lousy Church of God people."
Look at the example of Nineveh. God put that example in the Bible for a reason. We are to learn from it. There is more to learn from the book of Jonah that the length of time Jesus was in the grave. Read Jonah chapter 3.
Nineveh repented, yet was never called to conversion! What kind of repentance was that? Not the depth of repentance God must give as a gift prior to conversion and the receiving of the Holy Spirit. Probably, they never had a deep-down conviction that they were wrong, but they were merely afraid of the coming punishment. But at least they took Jonah's message seriously. And their effort to accept the message and try to stop sinning was enough for God to spare them the punishment He said he would bring upon them.
In a sense, they passed a test, but THEY HAD TO HEAR THE MESSAGE FROM JONAH TO PASS THAT TEST! No wonder God was determined to force Jonah to deliver the message. It was a vital part of God's plan for dealing with Nineveh and the example that this teaches us today (which might be more important to God than what happened to the Ninevites themselves).
Likewise, the message that the Church needs to deliver to the American people and all Israel BEFORE the tribulation begins may be a vital part of God's plan to bring about the fulfillment of Ezekiel 20:37-38.
We better deliver that message.
This may be something to think about during the Feast of Tabernacles, which is just a couple of months away. While we are planning our offerings, which will help finance and empower the preaching of a warning message to our nation, and while we are thinking about Israel being the model nation in the millennium, which the Feast of Tabernacles pictures, we should think about how our offerings directly help to bring about the world-wide utopia the Feast pictures.
God will use our holy day offerings to finance a warning message to help test all Israel, to see how each person reacts, to identify who the rebels are who will be destroyed in the tribulation, and who those are who will be most teachable in the millennium, who may survive to be the first generation of that model nation. Today we contribute to that process by our offerings, and in the millennium, after we are resurrected as the first fruits, we will directly be teaching those Israelites, and we will be glad God saved alive those who showed they were the most teachable. It will make our job easier. Then Israel will be a model nation that will help teach the world by their example. Thus the utopia will spread over the earth.
In the white throne judgment, resurrected mankind can compare the results of 6,000 years of Satan's way with the utopia of 1,000 years of God's way, and they will be able to make an informed decision that God's way is best. This will result in the salvation of the greatest number of people possible. That should be our goal.
What we do today can affect other people besides ourselves for eternity.
Here are links to related sections in Preaching the Gospel:
The Feast of Tabernacles - the Millennial Rule of Christ, Chapter 2
The Great Tribulation, Chapter 3
The Blessings and Curses, Chapter 3
The Responsibility of a Watchman, Chapter 3
The Ezekiel Warning, Chapter 3
The Two Witnesses and God's Fairness, Chapter 4
Why the Gospel Must Still Be Preached to the World, Chapter 4