What Is the Trinity and Where Does It Come From?

(Editorial note: This post was adapted from the sermon manuscript and transcript written and preached by Pastor Chris on Sunday, May 31, 2026 with the assistance of AI.)

The Trinity is the most contested doctrine in the history of the church.

That is not an exaggeration. Jehovah's Witnesses reject it. Latter-day Saints reject it. Oneness Pentecostals reject it. Unitarians reject it. Muslims reject it. Rabbinic Judaism rejects it. That is a strange group of people to agree on anything — but they all agree on this.

Which raises a fair question: did the church make it up?

It is one of the most common objections to Christianity. The Trinity, critics argue, was invented by church councils centuries after Jesus to consolidate power, control people, and impose a complicated theology that Jesus never taught. If that were true, it would be worth knowing.

But the evidence tells a different story.

What the Trinity Actually Claims

Before asking where the Trinity came from, it helps to understand what it actually says.

The doctrine of the Trinity is the Christian belief in one God — Father, Son, and Holy Spirit — three distinct persons, each fully God, eternally united in one divine being.

That is the claim. One God. Three persons. Each fully God. Eternally united. It does not resolve into a neat formula. It resists the kind of clean explanation people tend to want from their theology. And that resistance, more than anything else, is what has driven so many groups to reject it.

But the question is not whether it is easy to explain. The question is whether it is what Scripture actually teaches.

It Starts With One God

The foundation of the Trinity is not complexity — it is monotheism.

From the very beginning of the biblical story, God calls his people to worship one God and one God only. In Genesis 17, when God makes his covenant with Abraham, he names himself as the God of Abraham's family. Not one among many options. The God. The only one that matters.

By Exodus 20, the first commandment God gives at Sinai is clear: "I am the Lord your God. You shall have no other gods before me." That word Lord, printed in small capitals in most English Bibles, is the Hebrew name Yahweh — the personal name of God. What God is saying is that he, Yahweh, is the only God worthy of Israel's worship.

This is what made ancient Israel distinct. Surrounded by nations with multiple deities — gods for rain, for harvest, for war — Israel was called to one God alone.

But Something Strange Keeps Happening

Even within the Old Testament, God begins to reveal a complexity that simple monotheism cannot fully contain.

In Genesis 18, Yahweh appears to Abraham in human form — a person Abraham can sit with, speak to, and argue with about the fate of Sodom. In Exodus 3, the angel of the Lord appears to Moses in the burning bush, yet when the angel speaks, it is Yahweh who speaks. In Proverbs 8, God's wisdom takes on a voice of its own — present with God before creation, watching as the world was made.

None of these passages prove the Trinity on their own. But they establish something important: even in the Old Testament, God is more complex than a simple formula allows. Yahweh is in heaven. And yet Yahweh walks on earth. God is one — and somehow more than simple.

Then Jesus Shows Up

If the Old Testament hints at complexity, the New Testament makes it unavoidable.

Jesus does not merely teach about God. He claims to be equal with God. In John 5, Jesus calls God his own Father, and the text is clear that his opponents understood exactly what he meant — they wanted to kill him for it. In Matthew 26, when asked directly if he is the Messiah, the Son of God, Jesus answers by claiming to be the figure from Daniel 7 who takes a throne beside God in heaven. The high priest tears his robes and calls it blasphemy.

Jesus also makes clear connections between himself and the God of the Old Testament. He attributes the provision of manna in the wilderness to his Father. He tells his opponents that the God they claim as their own is his Father — and that his Father glorifies him.

These are not the words of a teacher who saw himself as merely a prophet or a moral example. They are the claims of someone who believed himself to be in a unique relationship of equality with the God of Abraham, Isaac, and Jacob.

And Then There Is the Holy Spirit

Before his death, Jesus promises his disciples that he will not leave them alone. He will ask the Father to send another advocate — the Spirit of Truth — to live in them, teach them, and remind them of everything Jesus said. The Father sends the Spirit in Jesus's name. Jesus also sends the Spirit from the Father.

By Acts chapter 5, the early church has already arrived at a remarkable conclusion. When Ananias lies about the proceeds of a land sale, Peter tells him: you have lied to the Holy Spirit. One verse later: you have not lied to human beings, but to God.

It did not take long.

What the Church Figured Out

The earliest followers of Jesus were faithful Jews. They believed in one God — Yahweh — and they were not looking to complicate their theology. The last thing they wanted was a new doctrine.

But they could not ignore what they had seen and heard.

Jesus claimed to be equal with God. He rose from the dead. He sent the Spirit. The Spirit came, and it was clearly God — personal, powerful, transforming. And yet these same people still believed, with everything in them, that there is only one God worthy of worship.

So they had to figure out what this meant.

The doctrine of the Trinity was not invented in a conference room. It was discovered through the slow, faithful work of people trying to be honest about what Scripture was showing them. Three persons. One God. Each fully God. Eternally united.

The groups that rejected the Trinity mostly did so because they could not explain it. So they simplified it. They made Jesus a little less than God. They reduced the Spirit to a force. And in doing so, they did not make God easier to follow. They made him smaller.

Why It Matters

The Trinity is not a theological puzzle to solve. It is a revelation to receive.

God has shown us who he is — Father, Son, and Holy Spirit. Not because it is easy to explain, but because it is true. And if we want to know God as he has actually revealed himself, the Trinity is where that journey begins.

At Salem Magley Church, we take the Trinity seriously — not because it is a tradition to preserve, but because we believe it reflects who God actually is. The triune God is the God we worship, the God we pray to, and the God who, through his Spirit, continues to work in the lives of his people.

[Watch the full sermon here.]