Not that God needs defending. God doesn’t need defending. But I have two friends—one ordained, one lay, both theologians—who don’t think the concept of the Trinity is essential. They believe that God is three and one, but they don’t think this is among the most important parts of our faith. When I first met these two and learned this about them, I had just graduated with a BA in religion from a Christian liberal arts school in West Michigan. I had been taught that the Trinity is foundational. These two friends are good people and Christ-followers both, so I was confused. I wasn’t willing to call them heretics, but I was also pretty sure they were wrong about this. Twelve years later they are among my dearest friends, and we laugh about those first conversations. We still don’t entirely agree, but I also see an awful lot of grace and a God who is big enough to hold all of us, with all of our ideas, and call us all beloved children.
And yet, I do believe understanding God as Trinity is essential to our faith. This is how God has revealed God’s self to us, and it affects the rest of everything. And so, for my friends, for my students who aren’t sure why they need to bother with theology and history, for any of you who may be unsure why such an abstract concept is more important than learning how to preach or manage the resources of a church, I make this defense of the Trinity.
A popular song from my middle school years sings, “I don’t care who you are, where you’re from, what you did, as long as you love me” (“As Long as You Love Me,” Backstreet Boys, 1997). A lot of my students think of God this way. They just want to know that God loves them (they just want to feel loved in general, but that’s a different conversation); they don’t care to learn about who God is. At least, their performance in my Intro Bible, theology, and history courses suggests that they don’t care about who God is. They just want to be loved, and, to their credit, they want to tell others about God’s love. I would argue that a person can’t fully understand what love is unless she knows the one who proclaims love. We interpret the phrase “I love you” differently based on the person speaking and the relationship we have. I love donuts; I love my best friend; I love my parents. We’re not confused about the kind of love when we hear the words because we know the person speaking. So how can we know the character of God’s love for us if we don’t know the character of God?
The ancients knew this. In the raging fourth-century arguments about the nature of God, a person couldn’t go to the bakery without being asked whether he was a homoian or a homoousian (Gregory of Nyssa, Oratio de deitate Filii et Spiriti Sancti [GNO X.2; PG 46.557]). The last time I was at Starbucks the barista only asked if I wanted whipped cream on my hot chocolate. It wasn’t that the ancients thought we could capture or fully understand the essence of God (that was a different heresy, among the Eunomians). They still claimed that God was mystery. But they also said that God had revealed God’s self to us, and we should try to understand what has been revealed so that we may know God more deeply.
The Trinity makes the most sense of Scripture and the experience of Christians. God is one. That has always been clear. But Jesus has done something radical. People experienced salvation with Jesus. Jesus rose from the dead. Athanasius says that Jesus restores the image of God in humans and reverses the world’s spin toward nothingness (On the Incarnation). After two centuries of trying to articulate the mystery of salvation they have experienced, Christians said that Jesus must be fully God, even as God is one. Therefore, God is somehow one and two—one divine essence and two persons. Then, that settled, they go through the whole process again with the Holy Spirit. The Holy Spirit also does the things that only God does, so they understand that the Holy Spirit is also fully God. Somehow God is one and three—three divine persons, one divine essence. This is how God revealed God’s self in Scripture and in Christ and in our experience of salvation and our continued existence and experiences of love in the world.
Having an understanding of the Trinity clarifies what it means to say or sing that God loves the world and that God loves us. Having this understanding keeps us from confusing God’s love with our love for donuts or, more probably, our parents’ and friends’ loves. To believe that God is Trinity is to believe that God loves the world so much that God became human in order to save it. To save us. To believe that God is Trinity is to believe that God is still active in the world, loving and sustaining it. It is to believe that, all empirical evidence to the contrary, the world could actually be worse than it is. To believe that God is Trinity is to hear and know the whole cosmic story of salvation. And then we know how much we are loved.