According to non-Trinitarians, why did God allow trinitarianism to become the mainstream understanding of His nature?

This answer draws and expands upon key points made by Emanuel Swedenborg (1688–1772), an 18th century scientist, philosopher, and theologian. During his theological period, which covered the last three decades of his life, Swedenborg rejected the Nicene Trinity of Persons. Instead, he taught a Trinity of "essential components" in a single Person of the Lord God Jesus Christ. For a plain English explanation of Swedenborg's Trinity, please see my article:

Who is God? Who is Jesus Christ? What about that Holy Spirit?

Summary

Swedenborg believed that by the time of the Council of Nicaea in 325 AD, when the Trinity of Persons first began to be established as orthodox Christian doctrine, the Christian Church was fast becoming corrupted by a desire for power and wealth on the part of its leaders. This caused its leaders to adopt doctrines such as the Trinity of Persons that would allow them to arrogate the power of Christ to themselves.

The alternative to the Trinity of Persons was Arianism, which ultimately denied the divinity of the Son, and thus of Christ. The primary doctrinal reason the Council of Nicaea was called was to condemn and reject the teaching of Arius about the Godhead. If this had not been done, Christianity would have died altogether.

By adopting the Trinity of Persons, a corrupt Christian leadership would still preach that Jesus is divine. The common people, who listen in simplicity to what their clergy teach them, could still be saved by a Christian faith and life.

In short, the reason God allowed the Trinity of Persons to become the primary doctrine of the Christian Church even though it is unbiblical and false is that the alternative was to allow the Christian Church to be rapidly destroyed, leaving the sheep without a shepherd.

Now for a fuller version.

1. Christ's church is founded upon a belief in his divinity

In Matthew 16:13–20 we read:

When Jesus came to the region of Caesarea Philippi, he asked his disciples, "Who do people say the Son of Man is?"

They replied, "Some say John the Baptist; others say Elijah; and still others, Jeremiah or one of the prophets."

"But what about you?" he asked. "Who do you say I am?"

Simon Peter answered, "You are the Messiah, the Son of the living God."

Jesus replied, "Blessed are you, Simon son of Jonah, for this was not revealed to you by flesh and blood, but by my Father in heaven. And I tell you that you are Peter, and on this rock I will build my church, and the gates of Hades will not overcome it. I will give you the keys of the kingdom of heaven; whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven." Then he ordered his disciples not to tell anyone that he was the Messiah.

The Roman Catholic Church commonly interprets this exchange to mean that Christ would found his church on Peter. It and other churches that claim apostolic succession believe that this gives the Church the authority to wield the power of Christ in administering the matters of the Christian Church, its people, and their salvation.

Swedenborg entirely rejected this interpretation. Instead, he said that it was Peter's statement, "You are the Messiah [or the Christ], the Son of the living God," upon which Christ was saying he would found his church.

In this understanding of Matthew 16:13–20, the Christian Church would be founded upon the belief that Jesus Christ is divine, and is God. If Christ is not divine, the Christian Church has no foundation.

Incidentally, Swedenborg also rejected the idea that the keys to the kingdom of heaven were given to Peter personally, and that this gave the Church the power to open and close heaven to people. Rather, he said that the passage refers to Christ's power to save "people who from a heartfelt faith have that confession of Peter" (Apocalypse Revealed #798).

2. Arianism threatened the foundation of the Christian Church

To this day, scholars debate exactly what doctrine about God Arius taught. However, due to teachings widely attributed to him—that the Son was subordinate to the Father, and that he was a creature of God (i.e., a created being)—the general tendency of Arianism was to make Christ less than God. This doctrine, followed to its logical conclusion, would ultimately result in the rejection of Christ's divinity.

Therefore if Arianism had been allowed to prevail in the church, it would have destroyed the foundation of the Christian Church, and the Church would have quickly fallen into ruins.

3. The Trinity of Persons fully affirmed the divinity of the Son of God.

In order to combat the Arians and their doctrine, the opposing Christian leaders had to formulate a doctrine that unequivocally affirmed the divinity of the Son of God. This the Trinity of Persons did, by proclaiming that the Son of God was begotten from eternity (which is not a biblical teaching), was a distinct "Person" of God (which is also not a biblical teaching), and was of the same substance as the Father (which draws more on Greek and Roman philosophy than on the Bible).

Although this doctrine introduced heresy after heresy into the church, it preserved the Christian Church's existence by affirming the divinity of Jesus Christ. This saved the church's foundation from destruction, and the church from rapid collapse.

4. The Trinity of Persons was the result of a corrupted church leadership

By the time the Council of Nicaea was called in 325 AD, the Christian Church had long since lost the brotherly love that had bound the early Christians together. It was now divided into warring camps, each attacking, anathematizing, and excommunicating the others.

In this atmosphere, the leadership of the Church could not accept the simple faith of the early Christians that Jesus Christ was "God with us" (Matthew 1:23), and that "in him dwells all the fullness of the Godhead bodily" (Colossians 2:9). Such a faith would require the complete humility of the Church's leaders at the feet of the Lord God Jesus Christ.

But these were not humble men. The Christian Church was fast becoming a State Church under the Roman Emperor Constantine. Its leaders wanted the power that association with the power of Rome would give them.

It would take too much time to explain how the Trinity of Persons allowed them to arrogate Christ's power to themselves. For now, just two points:

1. It was a strategy of "divide and conquer": divide God into three, and then conquer the church and the world using that dogma.
2. By making the human nature of Jesus like the humanity of any other man, it allowed the church leaders, as mere human beings, to step into the shoes of Jesus, and wield his power over the laypeople of the Christian Church.

On the practical level, it is a matter of history that from the time of Nicaea onward, armed with the doctrine of the Trinity of Persons and the power of the State, the Christian Church steadily accumulated more and more worldly wealth and power, until kings bowed down to popes, and the church was fabulously wealthy while the common people lived in poverty.

5. This made it possible for a corrupt church leadership to still preach Christ to the people

The Christian Church became more and more corrupt and worldly from the time of Nicaea onward. And yet, there were millions of ordinary good people—the sheep of the Lord's pasture—under its tutelage.

Because Christian leaders had adopted the Trinity of Persons, they continued to preach to the common people that Jesus Christ was divine. The common people did not understand the highly abstract and confusing doctrine of the Trinity of Persons. They only absorbed a belief that Jesus is the Son of God, and that believing in him and living by his commandments was the path to salvation.

6. The Trinity of Persons made it possible for good people to be saved even though the leadership of the Christian Church was increasingly corrupt

This is why God allowed the Trinity of Persons to become the reigning doctrine about God in the historical Christian Church.

It was a doctrine that the leadership of the church, which was motivated primarily by power and wealth, could accept, because it allowed them to arrogate Christ's power to themselves, and thus lord it over the people.

But it was also a doctrine that allowed laypeople of simple faith to accept Jesus as their God and Savior, and be saved by that faith and a life according to it.

The leadership of the Christian Church had become "like unmarked graves, which people walk over without knowing it" (Luke 11:44). Laypeople could have a simple saving faith in Jesus even as their leaders in the clergy brought spiritual death upon themselves by continually striving for wealth and power.

This vast accumulation of wealth and power by the Christian clergy, and the corruption that accompanied it, is a matter of history—as anyone who reads the ugly history of the Christian Church with objective eyes can see.

And yet, despite the rampant corruption among the clergy, millions of ordinary Christians of good heart and simple faith could continue to be saved, and make their eternal home in the heavenly kingdom of God.

This is the wisdom and power of Divine Providence, which uses evil humans and their false doctrines to accomplish God's own good and eternal goals.

7. Sources in Swedenborg's writings

The above answer is my formulation as a Swedenborgian scholar and minister. Swedenborg's statements on this subject are scattered throughout his writings, and require some familiarity with his overall theology to fully appreciate.

However, for those who wish to go to the source, here are several key passages in Swedenborg's theological writings:

• Divine Providence #262 discusses the proposition that "Doubts about divine providence may be raised by the fact that all Christendom worships one God in three persons, which is really three gods."
• Divine Providence #257 discusses the proposition that "Strict materialists justify their rejection of divine providence by observing that in many nations where Christianity is accepted, there are people who claim divine power for themselves and want to be worshiped as gods and who call upon the dead."
• True Christianity #632 discusses the proposition that "The concept of a faith that assigns us the merit and justice of Christ the Redeemer first surfaced in the decrees of the Council of Nicaea concerning three divine persons from eternity; from that time to the present this faith has been accepted by the entire Christian world."
• True Christianity #636 discusses the proposition that "The concept of a faith that assigns the merit of Christ was completely unknown in the apostolic church that existed before the Council of Nicaea; and nothing in the Word conveys that concept either."
• Swedenborg discusses the meaning of "Peter" and "the keys" in Matthew 16:13–20 in a number of places in his theological writings. Three of his clearest statements in rebuttal of the Roman Catholic Church's interpretation of these verses occur in Arcana Coelestia #2760; Apocalypse Revealed #768, 798.

Each of these passages offers source material on the reasons God allowed the Trinity of Persons to become the reigning doctrine in the Christian Church even though it is a human tradition that is unbiblical and false. Keep in mind that this material was written in the 18th century, and did not have the benefit of some of our present-day scholarship about Christian history.

According to non-trinitarians, if God's nature is not adequately portrayed by trinitarian theology, then why did God allow such an erroneous understanding of His nature to become so widespread among the members of the Church, the Bride of His Son? If God has the power and the prerogative to intervene in historical events, then why hasn't God made use of His divine privileges to ensure that the correct doctrine about His nature achieves widespread acceptance?

Its all part of our God and Father's master plan of redeeming the entire Creation back to Himself, in His Timing and according to what pleases Him.

The garden is infested with corruption from the king of lies. Our Father, the eternal 1 Farmer, is restoring His garden back to its intended glory on the earth. He has laid out this way in scripture by calling few to be a remnant of Truth and a light in the darkness. Right now, our high priest - the Risen Son, is calling priests to his better order. These will be the kings and priests of the next age. In the end days of this old and dying age, all Truth will be revealed by the Will of God.

Luke 12:2 KJV

For there is nothing covered, that shall not be revealed; neither hid, that shall not be known.

Jesus makes a clear distinction between those who will be allowed into the wedding feast and those who will not be ready:

Matthew 22:14 KJV

For many are called, but few are chosen.

Matthew 20:16 KJV

So the last shall be first, and the first last: for many be called, but few chosen.

What does this mean and why did our Master and teacher say this phrase more than once? Who are the virgins with oil? ...the few?

Matthew 7:13-14 KJV

13 Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat:

14 Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it.

John 15 KJV

16 Ye have not chosen me, but I have chosen you, and ordained you, that ye should go and bring forth fruit, and that your fruit should remain: that whatsoever ye shall ask of the Father in my name, he may give it you.

17 These things I command you, that ye love one another.

18 If the world hate you, ye know that it hated me before it hated you.

19 If ye were of the world, the world would love his own: but because ye are not of the world, but I have chosen you out of the world, therefore the world hateth you.`

Paul speaks of the Remnant spoken of throughout the Old Testement.

Romans 9 NASB

25....“I will call those who were not My people, ‘My people,’ And her who was not beloved, ‘beloved.’”

26 “And it shall be that in the place where it was said to them, ‘you are not My people,’ There they shall be called sons(children) of the living God(YHWH).”

27 Isaiah cries out concerning Israel, “Though the number of the sons of Israel be like the sand of the sea, it is the remnant that will be saved;

There are several instances throughout Revelation where John references an end times remnant.

Revelation 12:17 KJV

And the dragon was wroth with the woman, and went to make war with the remnant of her seed, which keep the commandments of God, and have the testimony of Jesus Christ.

In conclusion, the fact that Trinitarians are by far the LARGEST SECT of the MOST POPULAR religion of the WORLD, disqualifies the irrational man made theory from being the 1 Truth within the mind of our God.

.....But then again....simply using these 2 quotes of Jesus disqualifies the trinity much more efficiently.....ears to hear:

Mark 12:29-30

29 And Jesus answered him, The first of all the commandments is, Hear, O Israel; YHWH our God is 1 Lord:

30 And thou shalt love YHWH elohim with all thy heart, and with all thy soul, and with all thy mind, and with all thy strength: this is the first commandment.

John 17:3 KJV

And this is life eternal, that they might know thee the only true God, and Jesus Christ, whom thou hast sent.

Why did God allow trinitarianism to become the mainstream understanding?

It's not so much why did God allow... but, as we'll see, why didn't He?

If we go back to the Garden we'll start to see a theme in God's interactions with His creation.

• The Garden of Eden contained two trees - one a catalyst for evil, and the serpent who capitalised on this feature to tempt the first humans.

Clearly, God was not 'trying' to keep the perfect beginning perfect for long. He put in place the ingredients for it to get nasty quite soon. Whatever Adam's/Eve's nature and gifting was at the start, they were no match for the 'prince of the power of the air'.

God gave them some instructions, but He didn't seem to bother putting up warning signs and an electric fence to keep them away from evil. It was readily accessible. Neither did God banish the 'serpent' from this glorious beginning to another galaxy at least!

God starts something grand and let's evil have its way - to a point, and for a purpose, of His design.

• His nation Israel - a small nation with nothing particular to say, "Pick me!"

For you are a holy people to the LORD your God; the LORD your God has chosen you to be a people for His personal possession out of all the peoples who are on the face of the earth. Deut 14:12

7“The LORD did not make you His beloved nor choose you because you were greater in number than any of the peoples, since you were the fewest of all peoples, 8 but because the LORD loved you and kept the oath which He swore to your forefathers Deut 7:6

God did choose them and so began a tale of drama and tragedy with a promise of greatness, which all peoples would benefit from.

All peoples on earth will be blessed through you and your offspring. Gen 28:14

• Every one of God's chosen servants and prophets lived a life of distress and disappointment. The trust placed in their hearts was often the only thing they had to live on - hoping for a better tomorrow - even if it was millennia away!

To this day Israel has a veil over its eyes and hearts.

I do not want you to be ignorant of this mystery, brothers and sisters, so that you may not be conceited: Israel has experienced a hardening in part until the full number of the Gentiles has come in Rom 11:25

And even if our gospel is veiled, it is veiled to those who are perishing, 4in whose case the god of this world has blinded the minds of the unbelieving so that they will not see the light of the gospel of the glory of Christ, who is the image of God. 2 Cor 4:3

But their minds were hardened. For to this day, when they read the old covenant, that same veil remains unlifted, because only through Christ is it taken away. 2 Cor 3:14

God does what God does. He shapes matters according to His will and sovereign plans for the good of all. (not apparently obvious in this age, but the one to come)

• Why would the experience of the church be any different?

A fantastic beginning - the Messiah raised from the dead, the spirit given with wonders and signs, 1000's saved, and then as the apostles died the errors crept in. New teachings of men and political powers subverted the original truth about God's son and His plan for man. Perhaps some seemed innocent enough, but they distracted from the gospel and its simple message. Just as the serpent distracted the first humans from the words of God, so the strange teachings about Jesus' deity and other matters took away the focus Jesus had left with his anointed Apostles.

God has not rejected His people whom He foreknew. Do you not know what the scripture says of Elijah, how he appeals to God against Israel? 3“Lord, they have killed your prophets, they have demolished your altars, and I alone am left, and they seek my life.” 4But what is God’s reply to him? “I have kept for myself seven thousand men who have not bowed the knee to Baal.” 5So too at the present time there is a remnant, chosen by grace. Rom 11:2

• That the bible has been brought together with extreme effort and sacrifice, and yet also tampered with over the centuries is evidence enough that God's very (written) word is not untouchable - hence the church is greatly impacted. Not to mention all the other religions which, in part exist, because the church struggled to keep momentum and grow!

God could have stopped all kinds of evil before it began - but he did not. He never has unless it interferes with His plan. The story of Joseph is testament to that reality. There is good in there, but the woe and trial, the death and deceit is ever-present. Rather God steers evil for His purposes in this age of flesh until the appointed time is at hand.

According to plan, His son has defeated the source of evil and now waits on the Father to send him back to claim the spoils of victory already won.

If God has the power? There is no IF about it. It's more about timing not power.

Why hasn't God made use of His divine privileges? He hasn't yet in obvious fashion! But He has always interceded and worked things out according to His plan and nothing will cause Him to change course dealing with unexpected evils.

How do Non-Trinitarians answer? Trinitarian brothers and others who are believing in the same God who made all things and His son Jesus who died to save all men from an eternal death, are yet to see the plain truth of God's word and grasp the glorious victory Jesus has won - not by being God - but by being not God!

Indeed, he was made like us in every respect. Heb 2:17

A God/man is not like us at all!

The reality of this simple statement is foundational to understanding the bible without a pre-set bias - this bias caused by deception is allowed for a time - just as it has always been. God knows what He is doing, and the church/Christianity - in the terrible mess that it is in, is without the wisdom or the power to meet the world's needs or challenges. It will be prepared to be the pure and holy bride - it most certainly is not ready now.

Conclusion:

God doesn't need this age to be perfect. He fully intended to allow evil to strike at the heart of all He has prepared - knowing that in time, all will be restored and so much better than before. It will be better because it has experienced evil and the lies and deception that accompany evil.

Many are confused by this reality - thinking God should be able to make it right and keep it right. But the entire Bible tells a different truth if they are willing and able to see it. All will see it eventually.

Trinitarianism and many other heresies are part of the struggle He has allowed Christianity to endure. Just as it endures political forces and persecution in many ways.

God usually works with the smaller group, the struggling ones with little money, little influence and small resources. God wins out with small armies against larger armies, the isolated and victimised, the poor and the hungry - so long as those little ones trust and honour the 'one true God' Jesus and the other prophets taught about. No one can claim to be better than anyone else to know the truth of the Bible kept for us, it is only by God's grace that anyone can see the deception in the broader church. We can know by reading, but only with eyes to see and ears to hear will it make sense. Like Israel, His chosen people of promise, God will open their eyes and ears eventually when the time is right.

The deception that began in the Garden is absolutely thriving today. It is lie upon lie over the centuries that has caused there to be such deep confusion about God's word. It does not teach a trinity, an incarnation, a 'God the Son' deity, a holy spirit deity, an immortal soul, an eternal suffering in 'hell', and a lot of other things that most hold dear as non-negotiables. From the accounts of those God has called to His service, we can see how the church is no different. It will not be huge, wealthy, glamorous, powerful in the world, political. It will be small, powerful in spirit, poor and reliant on God not riches, and wise and it will hold to the word of God without adding in anything imaginative.

God has allowed this deception within Christianity because He is not saving the world now. He is saving a 'few' by comparison.

I have no doubt there will be trinitarians in the first resurrection. God is much bigger than labels and looks on the heart. He does not save through the church - he saves through Jesus. The church is the body of Jesus, not the head. (He may well 'cut off some parts' that are not serviceable and restore them at another time)

For the record, I do not speak for all Non-Trinitarians, but simply aim to present a Biblical answer to the following question:

If God has the power and the prerogative to intervene in historical events, then why hasn't God made use of His divine privileges to ensure that the correct doctrine about His nature achieves widespread acceptance?

God certainly could use His power to control everything, if not for His allowance of choice. God guides, yes, but He leaves it up to the individual whether or not they will heed His advice, as recorded here:

One of the things that God advises His people to do, through the apostles, is to be careful of the doctrines they believe in:

When it comes to God's nature, human beings have been prone to thinking up "foolish ideas of what God [is] like," going as far as to accidentally deify what was created, instead:

In particular, the Apostle Paul feared that peoples' minds would be corrupted in accepting a different Jesus and a different Spirit:

However, people will not always heed God's advice, in which case those people have no one to blame but themselves:

In fact, very few people actually choose life, indicating that the doctrine they believe in would not be widespread, with many more ending up on the road to hell:

It is foretold that those who would be consumed by fire, one thousand years after Judgment Day, would be as numberless as sand along the shore:

As the choosing of death is widespread, so too, then, unfortunately, is the rejection of the truth.

The standard historical answer is that the Church Fathers were heavily influenced by Greek culture and philosophical concepts, and imported those into Christianity. You then add to that a top-down imposition by Emperor Constantine, in particular.

Since about AD 400, anyone who said otherwise was persecuted. Remember you have Church monopolies in much of Christendom starting with it becoming a state religion in the Roman Empire. Even the Protestant reformation basically swapped a Catholic church monopoly in a given region with a Protestant state based monopoly. However, soon after the Protestant reformation (starting ~1500), you have non-trinitarian groups starting to emerge.

Servetus (~1550) was perhaps the earliest high-profile example, being a part of the Protestant Reformation but then in turn being executed for his Unitarian beliefs in 1553 by Protestants. Frances David was instrumental in the King of Hungary becoming a Unitarian (~1567). Socinus (~1580) was working with various Christian groups at the time, such as the Polish Brethren, and was widely influential. There were many Arian groups starting around the time as well. Racovian catechism 1605. John Biddle (~1650), believed to have translated the Racovian catechism into English, was imprisoned for his beliefs by Protestants but then exiled by Cromwell to avoid a trial. So very soon after the Catholic monopoly was lifted, many Unitarian movements started.

Jumping forward to the next century, we have Swedenborg 1750. By around that point, there were high-profile Unitarians in what would become the United States, such as John Adams. Mormonism 1820. Transcendentalism (such as Ralph Waldo Emerson) 1830's. JWs 1870's. Christian Science and related New Thought churches became a significant movement in the late 1800's and early 1900's. Similarly, it seems there is currently an uptick in Biblical Unitarianism.

Now for the theology. I think your question requires certain theological presuppositions that I don't hold. I would say blaming the Holy Spirit (i.e., God) isn't right - humans are in a fallen state, why would that not apply to collective theological beliefs?

From God's perspective, though, which beliefs are most important? Presumably those relating to salvation. Although trinitarians often hold that belief in the trinity is required for salvation, I am not sure the position is symmetrical with biblical unitarians. Indeed, God may not agree with trinitarians on this! Although trinitarianism is generally held to be some form of small 'i' idolatry among biblical unitarians, or perhaps just a conceptual error, when it comes to salvation emphasis seems to be placed on what John emphasized at the end of his Gospel (compare Matthew 16:15-17).

"But these are written so that you may believe that Jesus is the Christ, the Son of God, and that by believing you may have life in His name." (John 20:31)

The Bible doesn't say anything directly about trinitarianism, so to biblical unitarians it would be surprising that salvation requires belief in that! Both trinitarians and biblical unitarians believe that Jesus is the Christ and Son of God. They differ about whether he is God the Son, but that doesn't seem to be what is required in order to have eternal life, i.e., salvation, according to John.