We Christians believe that God is a Trinity, three persons in one God, and ours is the only faith that teaches anything even remotely like that. Now, you would think that what we believe about the inner life of God himself would have tremendous ramifications for other areas of our faith, but for most Christians, belief in the Trinity doesn’t seem to have much practical significance.
If you asked most people what Christianity would look like if you simply removed the doctrine of the Trinity, they would probably say that it would look exactly the same except for that one change. In other words, for most of us, taking the Trinity out of Christianity would make virtually no difference to our faith.
However, the Trinity is actually essential. It makes a huge difference to several of our beliefs, and without it, key elements of our faith would be very different. That may not be immediately obvious, so let’s take a look at two concrete ramifications the doctrine of the Trinity has for other areas of our faith.
God is Love
First, let’s look at the New Testament’s teaching that “God is love” (1 John 4:8). Most people, even members of other religions, would agree with this statement, but the truth is that we Christians are the only ones who can coherently affirm it.
When we say that God is love, we usually mean that love is an essential part of God’s nature. Loving is something that he does necessarily and all the time simply because of who and what he is. That seems fairly simple at first, but it raises a big problem. If God is just a single person, then he cannot really be love unless we, his creatures, exist. He cannot love to the fullest extent possible without us.
See, if we did not exist, God would only be able to love himself, and while self-love is a legitimate form of love, it is not the fullness of love. Rather, in its fullest form, love is directed outwards at someone else. It involves giving yourself to and for someone else, so if God did not have someone to love, he would not be able to love to the fullest extent possible. All he would have is self-love, but that is a lesser form of love. Simply put, without us, his love would be lacking, but if he truly is love, then his love cannot lack anything.
And that is problematic because God cannot depend on us for an essential part of his nature. He cannot need us in order to truly be who and what he is. In other words, if God truly is love, then he has to be love independently of his creation, but that is impossible if he is just a single person. However, if he is multiple persons, then it is possible. For one, the persons of the Trinity would still love one another even if we did not exist, and since they are truly distinct persons, that is not just self-love. No, the love between the persons of the Trinity is true, outward-directed love of the highest order, so God does not need us in order to love to the fullest extent possible necessarily and all the time.
Secondly, as a Trinity, God is essentially a family (and the model on which human families are based), a communion of love. His inner life simply is the love shared among the Father, Son, and Holy Spirit, so love is not just something he does. It is truly what he is, allowing him to be love in the deepest sense possible.
As a result of all this, while most people in our culture today happily affirm that God is love, only Christians can do so coherently. We’re the only ones who have the foundational beliefs that make this one possible, and that is incredibly important. While it may sound nice to say that God is love, you cannot truly affirm it if your beliefs about God’s nature do not allow it.
The Essence of Salvation
Secondly, let’s look at the nature of salvation. Again, we Christians often think that we share the same basic understanding of salvation as other religions, but that is not true. While there are of course some similarities, the Christian notion of our eternal destiny is much greater than anything any other faith has to offer. The New Testament tells us that our ultimate goal is to “become partakers of the divine nature” (2 Peter 1:4), a cryptic phrase that requires a bit of unpacking.
In a nutshell, if God truly is love, if his inner life is a communion of love shared among three persons, then to partake of his nature means to enter into that eternal communion of love. It means entering into the love that the Father, Son, and Holy Spirit share with one another, thereby becoming in a real (although limited) sense the very thing that God himself is. Granted, we can’t literally become God, but by entering into the communion of love that forms his inner life, we can get as close as possible.
And again, that is really significant. Because no other religion teaches that God is a communion of persons, only Christians can say that we will “become partakers of the divine nature.” Only we can believe that our ultimate goal is to enter into the very inner life of God himself, so our understanding of salvation and heaven is very different from that of any other religion.
The Trinity Matters
And that is just a sampling. There are other reasons why the Trinity matters, but those two are enough to show that the doctrine really is important. It has tremendous consequences for things like our understanding of God himself (even beyond the obvious) and our salvation.
In these areas, the doctrine of the Trinity leads our faith in directions that would simply be impossible if God were just a single person, so while we may not always give it much thought in our day-to-day spiritual lives, it defines our faith in a huge way, just as we should expect of such a unique understanding of the nature of God himself.