Three Crucial Questions About the Trinity: Finale (Why Is the Trinity So Important?)

We’ve been taking a look at one of the core doctrines of the Christian faith: belief in God as Trinity. We believe in one God who eternally exists as Father, Son, and Holy Spirit. As classical theologians have sought to explain it, God is “one Being, three Persons.”

In case you missed them, here are links to the previous posts:
1. Is it biblical? (Part One)
2. Where is it found in Scripture? (Part Two on the Old Testament, Part Three on the New Testament)

In this final post, we’re going to tackle the third crucial question: Why is belief in God as Trinity so important?

What practical difference does it make for our lives and our Christian faith?

1) It’s the most essential difference between Christianity and all other religions.

Underneath all of a person’s beliefs lies this key question: Which God do you believe in (or disbelieve in, if so happens to be the case)?

Is it the triune God of the Bible? If it isn’t, then no matter what you may wish to call your faith, it is not Christianity. (This is what I pointed out in my overview of unorthodox “Christian” sects, who all share a denial of the Trinity.)

Christian scholar Michael Reeves writes that “the Trinity is the governing center of all Christian belief, the truth that shapes and beautifies all others” (Delighting in the Trinity, 16). He also rightly points out:

“Jehovah’s Witnesses can believe in the sacrificial death of Christ; Mormons in his resurrection; others in salvation by grace. Granted, the similarities are sometimes only superficial, but the very fact that certain Christian beliefs can be shared by other belief systems shows that they cannot be the foundation on which the Christian gospel rests, the truth that stands ‘before all things.’ . . . For what makes Christianity absolutely distinct is the identity of our God.” — Delighting in the Trinity14-15.

Though belief in the Trinity may stretch the mind, and though we can never understand it completely this side of eternity, it remains the foundation for all Christian belief.

2) If God is not triune, he cannot be eternally loving.

This truth takes some unpacking, so hear me out:

Love is only possible when there are at least two present — a lover and a beloved. If God was just a unitary being who existed all by his lonesome before creating, then he would have had no one and nothing to love.

It would mean there was a time when God was not love.

It would also mean that love was not an intrinsic element of God’s character. It would be something added on later, when God created.

But the Bible asserts that love is essential to God’s nature. So much so that the apostle John can say, “God is love” (1 John 4:8). It’s his most defining characteristic! And because God is eternally perfect, he does not need to improve or add to his character (see Psalm 102:27; 90:2). He is eternally loving — always has been, always will be.

On the other hand, if you want a God who is eternally loving without being triune, you could claim that both God and creation are eternal (as some folks like to believe). But this does not fit the Bible’s teaching about creation at all. Jesus himself spoke of the glory he shared with the Father “before the world existed” (John 17:5).

Further, this view of God would mean that he was dependent on creation. As Reeves points out, “if God’s very identity is to be The Creator, The Ruler, then he needs a creation to rule in order to be who he is. For all his cosmic power, then, this God turns out to be pitifully weak: he needs us” (Delighting in the Trinity19).

The God of the Bible, on the other hand, does not depend on anything outside of who he is. He can be eternally loving because he has always existed as a loving community of Father, Son, and Holy Spirit. The three Persons of the Trinity shared an eternal love and glory before the universe ever began.

With such a God, creation was no necessity, but rather was the free overflow of the Trinity’s infinite, self-giving love.

3) The Trinity makes salvation by grace possible.

At the heart of the Christian faith is the recognition that, as Scripture teaches, salvation is entirely the gift of God; it is not something humans can achieve by their own efforts to please God (see Ephesians 2:8-10Titus 3:4-7).

Through his death on the cross, Jesus paid the price that our sins deserve. And when we place our faith in him, his perfect obedience is credited to us before God, we are restored to right relationship with God, and we have the hope of eternal life with God (see Romans 3:22-26; 2 Corinthians 5:211 Peter 3:18).

All of this is possible because of the Trinity.

Salvation as a gift we receive by faith is only possible because Jesus lived a perfect human life (as we have all failed to do) and died as our substitute. But this offering needed to be big enough to cover such an enormously vast amount of sins! How could one man’s life be enough to atone for the sins of the whole world?

Such a man would have to be of infinite value, of infinite perfection.

He would have to be God in the flesh.

If Jesus is not God, then his sacrifice was not enough to cover all of my sins, or all of yours.

This is why so many non-Trinitarian sects, such as Mormons, cannot fully affirm salvation by grace; they must tack on good works as well. By nature of their beliefs about God himself, they conclude that Christ’s sacrifice only takes people so far; it’s up to us to make up the rest with our own righteousness.

But such a picture is not what we see in Scripture, where good works are to be the outflow of salvation, the fruit of a life already made right with God, not the basis for earning salvation.

4) The Trinity helps us make sense of suffering.

Because Jesus is God in the flesh, and not just a mere human servant of God, we can look to the cross as the ultimate example of God’s self-giving love for us.

For me personally, this is one of the most powerful things about the Christian faith: at the cross of Christ, we see that God himself was willing to step into the worst of everything we humans can experience. He underwent rejection, betrayal, loss, suffering, and death. He took it all.

Unlike some critics of Christianity, we cannot accuse this God of “divine child abuse.” Because God is triune, Jesus’ death on the cross was a self-sacrifice — the ultimate self-sacrifice, in fact.

It wasn’t just a righteous man on that cross — it was God himself. The One who created me, the One I so often fail and sin against — he took my pain, my evil, my shame, my place.

No matter what mysteries remain about why God allows evil and suffering in his world, we can affirm what poet Dorothy Sayers put so well:

5) Because God is relational by nature, so too are humans who are made in his image.

Research has long shown that human beings are social creatures; we need community. So much so, in fact, that total isolation inevitably harms us. No wonder, since we are made in the image of a God who, at the core of his being, is relational.

If God were ultimately alone and unitary, then any attempt to become “godly” or like God would ultimately look something like monastic Buddhism or the like — isolating oneself and trying to achieve nirvana.

But if God is inherently relational (as the Bible in fact presents him), then really God’s intention for humanity is community; we’re meant to pursue genuine relationships with other people.

And as we grow in love for others, we actually become more like the God who is love.

This is exactly what Jesus and his apostles teach us. We’re to love one another, care for one another, know and be known by one another, as the life of God is manifested “where two or three are gathered in [Jesus’] name” (Matthew 18:20).

Love is so much at the core of what it means to know God that Scripture says anyone who is not in loving community with other Christians “does not know God” (1 John 4:7-8; see also John 13:34-35).

The triune God “is love in such a profound and potent way that you simply cannot know him without yourself becoming loving” (Reeves, Delighting in the Trinity26).

6) God is the ultimate model of unity-in-diversity, which is our calling as Christians.

If God is a Trinity, then his existence is one of diversity existing in perfect unity.

The Father is not the Son, and the Father and Son are not the Holy Spirit. They’re distinct, yet they exist in such perfect unity that they are one being.

When we read Scripture, we see that God’s intention for his people is that we be a united-but-diverse community — a fellowship of distinct individuals coming together in our common worship of God and pursuit of his mission.

In Jesus’ parting prayer for his followers, he asks the Father that “they may be one as we are one” (John 17:11).

“Oneness for the triune God means unity. As the Father is absolutely one with his Son, and yet is not his Son, so Jesus prays that believers might be one, but not that they might all be the same. Created male and female, in the image of this God, and with many other good differences between us, we come together valuing the way the triune God has made us each unique.” — Reeves, Delighting in the Trinity104.

In the last book of the Bible, heaven is depicted as a place where believers from every kind of diverse background come together to worship God in perfect unity:

After this I looked, and there was a vast multitude from every nation, tribe, people, and language, which no one could number, standing before the throne and before the Lamb. They were clothed in white robes with palm branches in their hands. And they cried out in a loud voice: Salvation belongs to our God, who is seated on the throne, and to the Lamb!” — Revelation 7:9-10

Heaven is not a place where our personalities are obliterated. Rather, the things that make us distinct — our ethnicity, our languages, our personalities — will all remain intact. And yet we will worship together in perfect harmony. This is part of the glorious hope that Christians have.

And it is also our present calling — to pursue, as best we can, such unity within the church. Even though such harmony will remain limited this side of heaven, we are nonetheless called to work toward greater unity.

We’re to be imitators of God (Ephesians 5:1), using our lives and our relationships as subtle pointers toward his triune majesty.


Phew! I know that was a long post, but hopefully you see now how significant belief in God as Trinity really is for the Christian faith!

If you want to go even deeper on the topic, I highly, highly recommend Reeves’ book, Delighting in the TrinityIf you couldn’t tell by how much I quoted it, it’s been an incredibly helpful resource for my own thinking on the subject.

I hope this series has been helpful to you! If you’re a seasoned Christian, it may have been familiar territory. But if I’ve mentioned anything that stood out to you, or left out something you’d like to have seen covered, drop me a comment and let me know!

See you down the path.

Categories: The Trinity, Theology

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