The goal here is not to give an exhaustive commentary on each passage but merely to show that there are very viable interpretations that are faithful to the whole of Scripture and do not lead to universalism.
“Turn to me and be saved, all the ends of the earth! For I am God, and there is no other.  By myself I have sworn; from my mouth has gone out in righteousness a word that shall not return: ‘To me every knee shall bow, every tongue shall swear allegiance.’”
In the LXX (the Greek translation of the Old Testament) απιστραϕητε is an imperative and means “turn around.” It has to do with changing ones beliefs and ways. It translates the Hebrew word (פָּנָה) meaning “turn” which is also in the imperative. So God here is not asking people to turn to Him, He’s commanding it. And it says that all people (from the farthest stretches of the earth) who turn to Him will be saved. But it implies that all who don’t turn to Him (in space in time before the Judgment) will not be saved. So we see precedence for “all” being saved here, that is, if any turn to the Lord from all over the earth they will be saved. Whosoever believes will be saved, Jew or Gentile. It was (in the OT and NT) an amazing thing for Paul for example that Gentiles can now be welcomed in (he called it a mystery). All the uncircumcised, the Egyptians that enslaved Israel, the Babylonians, all people that turn to the Lord (in space in time before the Judgment) will be saved. They will be saved from the terror of the Messiah’s Second Coming and the Final Destruction.
In the context, this passage would strike fear into the hearers, not comfort. This passage is saying, “repent and turn or else!” Further, v. 25 says “all the offspring of Israel shall be justified,” i.e. all those who have faith (see e.g. Rom. 2:28-29; 4:1-16; 9:6), not all without exception. “Yahweh’s speech ends with a prediction of destructive fire for those who do not submit to his reality and reign (Isa 47:14-15)… There is voluntary submission for some and involuntary submission for others.”
All throughout the Bible, from Genesis to Revelation, we see two distinct groups. God has called particular people from all nations. As James Hamilton has said, “People are either seed of the serpent, on the side of the snake in the garden, or seed of the woman, on the side of God and trusting in his promises.”
The careful reader of Scripture can see the enmity between the two seeds in Genesis and in fact through the whole Old Testament. There are physical decedents of Eve that are spiritually seed of the serpent. This is not just something we see in the Old Testament though. We see it through the whole of Scripture (cf. e.g. Matt. 13:38; Jn. 8:44; 1 Jn. 3:8). We see two distinct seeds with two distinct ends from the beginning of Genesis (cf. esp. Gen. 3:15) to the end of Revelation (cf. e.g. Rev. 21).
Notice that in 2 Thessalonians 1:7-10 there are two groups: 1) those who did not believe and thus receive judgment and 2) those who do believe and thus enjoy the presence of God and marvel at Him. And notice Jesus separates the goats from the sheep based on what they did in their earthly lives (Matt. 25:32ff). People are gravely either goat or sheep, wise or fool, darkness or light, faithful or faithless, in Christ or damned.
As I have said, the Bible shows to different humanities, one lost and the other saved, one in heaven and one in hell. This is what we see throughout the story of Scripture and this is what we see reflected in other places in the early church’s teaching. For instance, the Didache (50-120AD) says, “There are two ways, one of life and one of death, and there is a great difference between the two ways” (1:1).
As a protestant who believes in sola Scriptura (Scripture alone), I believe that tradition and confessional Christianity does not hold a place above Scripture. However, I do believe it is important and helpful to consider what church history has to say on theological issues. So let’s look briefly at the question of whether or not universalism has been accepted in historical confessional Christianity.
Harold J. Brown makes an interesting point that we should consider. He says,
“curiously enough, it is heresy that offers us some of the best evidence for orthodoxy, for while heresy is often very explicit in the first centuries of Christianity, orthodoxy is often only implicit. If we hope, today, that the orthodoxy we believe is the ‘faith once delivered to the saints’ (Jude v. 3), then it is necessary to assume that it is older than heresy. But heresy appears on the historical record earlier, and is better documented, than most of what the church came to call orthodoxy. How then can heresy be younger, orthodoxy more original? The answer is that orthodoxy was there from the beginning and heresy reflected it. Sometimes one catches a glimpse of another person or object in a mirror or a lake before seeing the original. But the original preceded the reflection, and our perception of it. The same, we could argue, is true of orthodoxy—the original—and heresy—the reflection. The heresy we frequently see first, but orthodoxy preceded it.”
False teachings call into question the pillars of Christianity and so teachers and creeds rise up in protection of the church’s foundational teaching. The doctrine of the Trinity has always been orthodox but there has not always been a creed stating such. The reason for this is because false teaching gives rise to defensive of orthodox teaching. Thus, in history we often see heresy argued before we see orthodoxy defended. Greg A. Allison says that the “issue of the continuation of punishment for the wicked became a point of debate with the theology of Origen” (c. 185-254) so it makes sense that universalism was not formally acknowledged as heresy until later on.
Everett Ferguson says that
“apart from Origen, who entertained the possibility of universal salvation after a period of purification and education of souls in the afterlife, those who spoke to the subject understood an ultimate division of humanity in heaven or hell. The expectation of eternal reward sustained Christian endurance in the face of persecution and other hardships.”
W. G. T. Shedd wrote:
“The common opinion in the Ancient church was, that the future punishment of the impenitent wicked is endless. This was the catholic faith; as much so as belief in the trinity. But as there were some church fathers who deviated from the creed of the church respecting the doctrine of the trinity, so there were some who dissented from it in respect to that of eternal retribution. The deviation in eschatology, however, was far less extensive than in trinitarianism.”
Allison demonstrates in his book Historical Theology: An Introduction to Christian Doctrine that
“from its inception, the church has believed that there will be a final judgment of both believers and unbelievers… On the one hand, this judgment will usher believers into the presence of Christ and the blessedness of heavenly reward forever. On the other hand, following the judgment of condemnation, unbelievers will experience eternal conscious punishment in hell. Only a few Christians deviated from this understanding of the last judgment and eternal punishment.”
A few more examples:
“As regards the fate of the wicked… the general view was that their punishment would be eternal, without any possibility of remission.”
“Everlasting punishment of the wicked always was, and always will be the orthodox theory.”
“The punishment inflicted upon the lost was regarded by the Fathers of the Ancient Church, with very few exceptions, as endless.”
“Church creeds from the early Middle Ages through the Reformation and into the modern era regularly affirmed the eternal punishment of the wicked… The reality of hell and eternal punishment was thought to be as basic to Christian belief as the Trinity and incarnation.”
There is a certain way we should approach questions, the first thing that comes to mind is humility. There are certain things we cannot know the definitive answer to. I think that makes sense since we are creation, not Creator. However, that is not to say we shouldn’t ask. Here are a few of my thoughts on the question…
First, is it actually big? It’s all perspective. To us it seems big, big beyond comprehension. However, Isaiah 40 says that God names every star and that the nations are like dust on a scale. That is, things, even really big things, are small to God. Also, to put things in perspective, ants seem small to us but they don’t seem small to themselves. There are things that are small compared to ants (e.g. protons and neutrons). Maybe it is not the universe that is big but we that are small. Maybe that seems strange because we see ourselves as so big, so grand. Maybe that’s part of the reason the universe is so big, to show us that we are small. We are not the be-all-end-all of the universe. We are small.
Second, the Bible says that the heavens, i.e. the vast universe, carries out a specific role. And what is that role? The vast universe declares the glory of God (see Ps. 19:1ff; 50:6; Rom. 1)! If the universe is declaring the glory of God it makes sense that it would need to be big!
Third, God takes pleasure in His creation. There are stars no human will ever see, fish we can’t imagine, and flowers that bloom and die without any humans awareness. But God knows. And God takes pleasure in it all. Remember, in Genesis 1:31 God said it was “very good.” So, God enjoys His vast creation. Remember God is the Great Creator, the Great Artist. Artists create. And it’s awesome and beautiful and sometimes mysterious but it’s what they do, even if no one sees. Creator or Artist is part of who God is, it’s one of His attributes. It’s what He does
Fourth, it causes us to say, “What is man that you are mindful of him” (Ps. 8:4)? It makes us amazed that God the Creator and sustainer of all, the one who upholds the universe by the word of His power, cares about us. Even to the point of death on a cross.
[In fact, the hardest thing in all the Bible for me to believe is not the resurrection, is not the miracles, is not any of that stuff, that all makes sense to me (God can do all that!). However, what is hard to believe is that God cares about us humans. That is amazing!]