Fathers of the faith came up against the same flavors of heresy that we do today, and to battle against these false doctrines they opened Scripture and wrote creeds to help ordinary believers understand. Thanks be to God, he has preserved these creeds, and confessions in more recent history, for us today. While the creeds don’t carry the authority of Scripture, they communicate and summarize the essential truths of Scripture. I recommend getting to know the Nicene Creed and the Athanasian Creed, which were specifically created to summarize the teaching of Scripture and condemn trinitarian heresies.

Have you ever found yourself trying to explain the Trinity to a child? Or perhaps even a teen or adult who has never heard of the concept? I have three little ones, one of whom is a four-year-old bubbling with questions. Here is an example of a recent bedtime conversation we had:

“Mommy, what is the Trinity?”

“The Trinity is God. Three Persons, one God.”

His face scrunched up. “How can God be three Persons but one God?”

This is where I should be able to tell you I gave the most perfect, theologically sound answer to my child and tell you how you can do the same.

I did no such thing.

“Um… well… he just is.”

“But how did Jesus come to earth and the Father remain in heaven?”

“Well, I… um…”

“How is God a Father and a Son?”

Many Christians struggle with how to give a sound explanation of the Trinity.

As I grappled and hummed, my four-year-old kept listing off question after question—none for which I had an answer. I was tempted to use one of those explanations I had heard in church growing up: God is like an egg, God is like the three forms of water, God is like a flower… but I knew that all those fell flat because, in one way or another, they all promoted a trinitarian heresy.

For years, I’ve prided myself on my passion for theology and biblical literacy, and my shelves sagged with heavy academic books. But as I tucked my child in that night, I was humbled by my lack of a basic understanding of the Trinity.

I have a feeling I’m not alone. You don’t have to be a mother to be faced with the dilemma of explaining the Trinity. You could be a Sunday school teacher (for any age) being asked to further explain, or reclining at a family meal where the conversation of religion comes up. Or maybe you’ve stood in your doorway with someone evangelizing to you about their religion that seems to mirror Christianity but smells of tritheism. Or perhaps you’re alone studying your Bible and wondering how God can possibly be three Persons and one God. Let’s open our Bibles and get to know the Trinity together. But first, in case you’re still not fully convinced you need to know this, let’s dive into why the Trinity matters.

Our theology of the Trinity affects our fundamental understanding of what Christianity means.

Because of how convoluted and confusing this doctrine can appear, we may be tempted to push it to the side. We loop it in with doctrines such as the end times and say, “It’s something we just won’t be able to grasp this side of heaven.” But the doctrine of the Trinity is essential to Christian theology. When we get the Trinity wrong, we get all of Christianity wrong. That’s what makes first-order Christian doctrines so vital to our faith: Everything that we believe is rooted in them, and once you alter those ground-level doctrines it changes how the entire tree grows. The Trinity is no different.

If we don’t emphasize the oneness of the Trinity correctly, we move towards tritheism—the worship of three gods rather than one. This breaks the first commandment (Exod. 20:2–3) and goes against God’s clear revelation of him: “Hear, O Israel: The LORD our God, the LORD is one,” (Deut. 6:4; cf. Mark 12:29; John 17:3; Rom. 3:30). But if we blend them too much together, we get another heresy that goes against the clear revelation of the three distinct Persons (Gen. 1:1–27; Matt. 3:13–17; John 1:1–5).

Getting the Trinity wrong likewise skews the gospel message by which we are saved. Did one of our gods die for our sins after the greater god told him to? Or did the Second Person of the Trinity, the Son of God, die in our place because of a covenant made in eternity past between the three perfect, eternal Persons of the Godhead? Does a lower, lesser god indwell us, or does God himself indwell us through the Third Person of the Trinity? These questions matter, and they change the whole of our salvation when answered wrongly.

Even if we aren’t the ones falling for these false doctrines, we need to be prepared to give the right answer to those who ask (1 Pet. 3:15). These people might come into your classroom, bump into you at church, sit in your small group, or knock on your front door. Will you give them biblical truth? Will you be able to defend what you believe?

Inconspicuous Trinity “drifts” can still be found around us.

The examples I gave above are a bit on the further end of the spectrum, and likely you won’t encounter them to that extreme in your church, books, podcasts, blogs, or social media feed. But that doesn’t mean the Trinity isn’t still skewed in evangelical theology.

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