What is the Trinity? Think about it for a minute. How would you explain this doctrine to someone who’s never heard of it? It’s pretty difficult right? Are there three Gods or only one? Is the Father the greatest God? Did he create the Son and the Spirit? Is each person one-third God or fully God? The questions are almost endless.

Despite the difficulty, Christians should seek to understand the Trinity because it’s the doctrine that makes Christianity unique. It’s so fundamental to the faith that to miss it means to miss Christianity. That’s not an overstatment. It’s that important.

So, in the remaining space, I’d like to provide an elementary introduction to the Trinity. My hope is that you will both understand this doctrine and delight in it at the same time. After all, God doesn’t simply want us to understand his nature. He wants us to love him — to enjoy him. My prayer is that this brief article will help lead you to do just that.

THE FATHER, SON, AND HOLY SPIRIT ARE EACH GOD

Christians have affirmed, dating back to the earliest centuries that the Father, Son, and Holy Spirit are each God. The ancient Nicene Creed affirms this claim, but the church fathers who wrote the creed reached their conclusions based on Scripture. That is to say, Scripture was and is the final authority for Christian dogma.

THE FATHER IS GOD

What does the Bible say, then, about the deity of each person? It unequivocally declares that the Father is God. So much so, that hardly anyone denies this. For example, 1 Corinthians 8:6 affirms, “for us there is one God, the Father, from whom are all things and for whom we exist.” Additionally, in John 17:3, Jesus prays to the Father and declares, “And this is eternal life, that they know you, the only true God.”

THE SON IS GOD

The Bible also affirms that the Son is God. John 1:1 asserts, “In the beginning was the Word, and the Word was with God, and the Word was God.” We know that the Word refers to the Son because just a few verses later John tells us, “And the Word became flesh and dwelt among us, and we have seen his glory, glory as of the only Son from the Father, full of grace and truth” (Jn. 1:14).

Notice John 1:1 asserts that the Son is both with God — that is, he’s distinct from God — and, at the same time, he is God. John doesn’t give us the full Trinity here, but he declares that the Son is on the same level with the Father. He, likewise, has existed from the very beginning — an obvious reference to Genesis 1:1. In fact, two verses later John tells us “All things were made through him (the Word), and without him was not anything made that was made” (Jn. 1:3). That is, the Father created through the Son.

THE HOLY SPIRIT IS GOD

Finally, Scripture teaches that the Holy Spirit is God. In Acts 5, Peter confronts Ananius and Sapphira for their deceit. He asks, “Ananias, why has Satan filled your heart to lie to the Holy Spirit to keep back for yourself part of the proceeds of the land?… You have not lied to man but to God” (Acts 5:3-4).

Notice that Peter accuses Ananius of lying to the Holy Spirit and, at the same time, tells him that he lied to God. That is to say, the Holy Spirit is God.

Additionally, Paul affirms the Holy Spirit’s deity in 1 Corinthians 3:16. “Do you not know,” he asks, “that you are God’s temple and that God’s Spirit dwells in you?” Notice specifically who dwells in the Christians. On the one hand, Paul can say God dwells in you, when he says you are God’s temple. And on the other hand, Paul can say the Holy Spirit dwells in you. In other words, the Holy Spirit is God.

THERE IS ONE GOD

If we stopped right here, we might be tempted to think that the Bible teaches three Gods. But that would be a mistake. Scripture uniformly teaches that there is only one God.

Take Genesis 1:1 for example. “In the beginning, God created the heavens and the earth.” Which God? The text implies that there’s only one. It doesn’t distinguish between different Gods because the one and only God created all things.

Several times throughout the Old Testament, God affirms that he’s the only God. He declares in Isaiah 45:5, “I am the LORD, and there is no other, besides me there is no God.” Elsewhere he proclaims, “I am the first and I am the last; besides me there is no God” (Isa. 44:6).

Perhaps the most quoted Old Testament text among the Jews teaches that there is only one God. Deuteronomy 6:4 exclaims, “Hear, O Israel: The LORD our God, the LORD is one.”

TRINITARIAN TEXTS

So far, we’ve observed several texts that indicate the Father is God, the Son is God, and the Holy Spirit is God. And we’ve looked at several texts that affirm only one God exists. 

With the exception of the John 1 text, though, none of these texts by themselves give us a robust representation of the Trinity. Therefore, in this section, I’d like to highlight two different texts that put the Trinity on full display.

MATTHEW 28:18-19

In the Great Commission, Jesus proclaims, “All authority in heaven and on earth has been given to me. Go therefore, and make disciples of all nations, baptizing them in the name of the Father, and the Son, and the Holy Spirit.”

A few quick observations are in order here. First, notice that Jesus says we are to baptize in the “name,” that is the singular name of the Father, Son, and Holy Spirit. Not “names” but “name.” So, on the one hand, Jesus affirms there’s only one name. On the other hand, however, he affirms that all three persons of the Godhead share that name. Additionally, he implies each are co-equals. There’s no hint that one is more God than the others.

MATTHEW 3:16-17

We read, “And when Jesus was baptized, immediately he went up from the water, and behold, the heavens were opened to him, and he saw the Spirit of God descending like a dove and coming to rest on him; and behold, a voice from heaven said, ‘This is my beloved Son, with whom I am well pleased.’”

Notice that this text presents all three members of the Trinity as simultaneously distinct from one another. One of the more popular Trinitarian heresies, known as modalism, teaches that God is only one person who manifests himself as different persons — or modes — throughout history. For example, modalists say God manifested himself as a Father in the Old Testament, as a Son during the Gospels, and now as the Spirit after Jesus’ ascension. 

The problem for modalism, though, is it ignores texts like this one which affirms that all three persons exist simultaneously and relate to each other.

THE TRINITY DEFINED

At first glance, it looks like we’re bad at math. Three entities are God, but there is only one God. It’s head-scratching stuff no doubt. It’s easy to see why the early church wrestled over this. They rightly saw that the Father, Son, and Spirit were all God. But at the same time, they recognized the Bible taught that there’s only one God. On the one hand, they saw “threeness,” and on the other hand they saw “oneness.” This is where we get the term Trinity. “Tri-unity” meaning three in one.

In order to maintain the “threeness” and “oneness” of God at the same time, the early church had to define certain terms. First, they declared that the “threeness” referred to the Persons of the Trinity. That is, three distinct Persons exist co-eternally in the Godhead. We should recognize, they said, that the Father is not the Son or the Spirit, the Son is not the Father or the Spirit, and the Spirit is not the Father or the Son.

Second, the early church expressed that the “oneness” referred to God’s essence or his nature. That is, the different persons of the Godhead — the Father, Son, and Holy Spirit — all share in the divine essence. Just as the Father is eternal, the Son and Spirit are eternal. Just as the Father is love, the Son and Spirit are love. As the Father is all-knowing, the Son and Spirit are all-knowing. You get the idea. 

Thus, the early church affirmed, as they saw it in Scripture, that the Father is fully God, the Son is fully God, and the Spirit is fully God, yet there is one God. 

So how should we define the Trinity? Here’s a good definition:

There is one God who exists eternally as three distinct persons — the Father, the Son, and the Holy Spirit — and each of these persons is fully and equally God.

LOVE THE TRINITY

Imagine one day your spouse informs you that there is something really important about them that is difficult to understand. They recognize that you might not fully grasp all the details, but because they love you, and they want you to love them for who they are, they share the difficult details with you.

What kind of spouse would you be if you said, “you know what, this is too hard for me to understand. I’m not even going to try”? I’d say you’d be pretty terrible. Because a loving spouse desires to know everything they can about the one they love.

In the same way, if we say we love God, we should strive to know everything we can about him. This doesn’t mean we’ll fully understand everything. After all, the Trinity is really difficult to grasp. But at the same time, God has chosen to reveal himself to us as a Trinity which means he thinks it’s really important for us to know that about him. 

So, consequently, you should attempt to understand the Trinity. Unless, of course, you don’t love God. But what Christian is going to admit to that?