When you think of the most important Christian doctrines, the beliefs that are most important for our faith, what comes to mind? I’d be willing to bet that for most people, things like the Incarnation and the resurrection of Jesus are probably at the top of the list. Christianity is named after Jesus Christ, so what we believe about him is pretty important for our faith. However, I would suggest that there’s another doctrine that’s just as significant: the Trinity.
We don’t normally think of the Trinity as having much practical significance for our faith, but it’s actually very important that there are multiple persons in the one God. If there were only one, then Christianity would be radically different. That may sound like a bold statement, but hear me out. Let’s take a look at a few key passages of Scripture and see what light they can shed on the difference the Trinity makes for our faith.
The Nature of God
First, let’s look at a text that we usually just pass over without giving it a second thought:
God is love. (1 John 4:8)
In our culture today, this has become almost a cliché. Both Christians and non-Christians usually agree that God is love, so it may at first be hard to see how this can have anything to do with the Trinity. But think about it a bit more deeply. The verse doesn’t just say that God loves a lot; no, it says that he is love. Love isn’t just something that God does; it’s what he is. Now, since God is perfect, if he is love, then he must be perfect love; he has to be the fullness of love. In other words, his nature simply is to love perfectly at all times, and that’s where the Trinity comes in.
See, if God were just a single person, then for him to love perfectly at all times, he would need someone else to love, which means that he would actually need us, his creatures. Yes, he can love himself, but self-love isn’t the fullness of love. In its fullest form, love is directed outwards at someone else. It involves giving yourself to and for another, so without another person to love, God can’t truly be love. However, since we’re only his creatures, God can’t need us for anything, so he couldn’t be love if he were just a single person. On the other hand, if he is a Trinity of persons, then he can be the fullness of love. Each person of the Trinity can love the others, and since they’re distinct persons, the love they have for one another can be the fullest, most perfect form of love possible. They truly give themselves to and for one another, so their love doesn’t lack anything.
And that’s not all. As a Trinity, God can be love in an even deeper way: he is a communion of love. His inner life simply is the love shared among the Father, Son, and Holy Spirit, so in the deepest sense possible, he truly is love. As a result, even though it has become commonplace in our day and age to say that God is love, only Christians can truly affirm it. Only if God is a communion of multiple persons can he really be love.
The Nature of Salvation
And this makes a huge difference in other areas as well. For example, elsewhere in the New Testament, we read that our goal as Christians is to “become partakers of the divine nature” (2 Peter 1:4), and once we understand what it means for God to be love, this verse takes on a whole new meaning. It means that our ultimate goal is to enter into the communion of love that the Father, Son, and Holy Spirit share. It means that through his grace, God allows us to enter into his inner life and become the very thing that he is (granted, we can’t fully become God, but he allows us to join him as much as we possibly can).
He makes us enter the communion of love that constitutes him, and that’s possible only because there are multiple persons in the one God. If there weren’t, we would never be able to enter into his inner life. If God were a single person, we could never become part of the very thing that constitutes him. However, because God is a Trinity, we can unite ourselves to him and partake of his nature in a radical way that no other religion envisions.
The Difference The Trinity Makes
And that’s the difference the Trinity makes. It’s not just a mind-bending idea for theologians and philosophers to have fun contemplating and debating. It’s not just a fun tidbit to know, like a friend’s middle name or their favorite color. No, the fact that there are three persons in the one God has huge implications for our understanding of both his nature and our salvation. Because he’s a Trinity, he can truly be love in a way that would be totally impossible if he were just one person, and because he is love, our eternal salvation involves entering into his inner life in a way that we could never do otherwise. Simply put, the Trinity makes Christianity radically different from every other religion. No other faith teaches that we can enter into the inner life of God as intimately as ours does. No other religion teaches that we can truly become what God himself is (inasmuch as we are able, of course).