I think the reason this question resonates with so many parents is precisely because we adults can’t adequately explain the doctrine ourselves. We can teach children the inerrancy of Scripture by simply saying, “The Bible Is True.” We can explain something of the atonement by saying, “Jesus paid for our sins and is alive forever.” The Trinity, though, is another matter.
I think much of our fear and stumbling here comes with a misunderstanding of what the Christian gospel is all about. Yes, Christianity is reasonable and intelligible (Carl Henry stands affirmed).
But Christianity is not merely about reason and intelligence. The gospel points to a different kind of wisdom, one that silences human mouths (Isa. 55:8; Jer. 8:9; 1 Cor. 1:19-20).
God is one God, and God is three persons in an everlasting relationship with one another, a relationship into which we are invited. That’s not contradictory. God is not one in the same way he is three, or vice-versa. But who can reduce this to some sort of formula or easy analogy?
Sometimes we seek a quick analogy for children because we want to put our kids out of their mystery. If the Trinity is an easy explanation (it’s like a shamrock; it’s like water, ice, and steam), we can “move on.” We’re afraid if we say that the Trinity is in some ways beyond comprehension that our kids won’t trust us to tell them with confidence about the truth of the gospel.
But Jesus tells us there’s something about a child’s way of believing that ought to be true of all of us. We must, he tells us, become like them if we’re going to enter the kingdom of God at all. In one sense, it’s true, children are often hyper-literal. I remember thinking as a child that a “soul” was a little version of myself located in one of the chambers of my heart (and wearing a soldier’s uniform, for some reason).
But, in the more important ways, children are open to mystery and paradox in ways adults often aren’t. Children explore the world around them with a wide-eyed sense of wonder. They don’t comprehend it all, and they know they don’t comprehend it all.
That’s the kind of blessed ignorance I believe Jesus commends. In order to believe, you must trust everything God has said to you, but you must also see him, not your own comprehension, as Lord. To see at all we must know that we “see through a glass darkly” (1 Cor. 13:12).
With that the case, we ought to boldly say to our children, “God is One and God is three. I can’t fully explain all of that because that’s how big and mysterious God and his ways are. Isn’t that wonderful?” When your child says, “That boggles my mind,” don’t respond with a worried handwringing but with a twinkle in your eye. “I know!” you say. “Me too! Isn’t that wild, and great!”
That doesn’t end the conversation, of course. It only begins it. But we’ve got several trillion years and beyond to explore the depths of the Trinitarian reality. A start is what we need.
And learning of God’s oneness and threeness in terms of wonder and awe is a good place, I think, to start vaccinating our children from the kind of sterile rationalism, Christian or atheist, that can lead to a boring, despairing, tragically normal sort of life.