The Bible is clear that there is only one God: “Hear, O Israel: The Lord our God, the Lord is one” (Deut. 6:4). Yet, the New Testament and, later, the creeds and liturgies of the church, also present God as three: Father, Son, and Holy Spirit (Matt. 28:19). The three belong to the eternal oneness of God without losing their distinction as three, since their mutual communion of love is eternal (John 17:5, 24). Now, here’s a basic problem: How can the triune God as Father, Son, and Spirit be both “one” and “three?” Do we not face here a mathematical problem?
Put differently, can we count the Triune God? Can we treat the one God who is three as a mathematical problem? I am no expert in math; in fact, it was my most difficult subject in college. But as a theologian, I can say with a fair amount of confidence that the divine oneness and threeness of God cannot be reduced to counting as we are accustomed to count without giving rise to misleading implications. Peter van Inwagen rightly notes that there is no “absolute counting” when it comes to God. To start with, one has to ask in reference to God how one is to count. If we count according to gods, God is indivisibly one. But if we count according to persons, God is three.[1]
To complicate matters further, one can say, on the one hand, that God’s indivisible oneness necessarily involves the three persons-in-relation named Father, Son, and Spirit. The reason is that Love is relational, perfected within a gracious communion of life. If God not only loves but is love in infinite perfection, God would arguably be a communion of life. In the light of the biblical narrative, the divine oneness would lack perfection without the communion of three. Walter Kasper is correct: “For this reason, once God is thought of from the start as personal, the oneness and unicity of God cannot possibly be conceived as meaning a solitary God.”[2] In the context of the biblical narrative, this means that the one God who loves perfectly in freedom involves one who loves (Father), a beloved (the Son), and the freedom and ecstasy of this love overflowing in unselfish and free delight (the Spirit). The Father is the source and the Spirit the crowning of God’s incomparable oneness. In other words, the “One and Only God” would not be the one that God is without the three. “One” as a mere number fails us here.
On the other hand, the three cannot be the three that God is without being the one. This is because the three are not separate parts each representing one-third of God. If this were so, the persons would each lack perfection since they would individually border and limit each other. Even together they would lack the perfection of the uniquely indivisible God, since a collection of separate and limited parts does not cease being separate and limited parts because they’ve formed an alliance and partner in shared lives and actions. In Trinitarian theology, the indivisible oneness of God means that the three distinct "persons" are indivisible in that they subsist in the one being of God, sharing in the fullness of the divine life under that which is appropriate to the persons (Father, Son, and Spirit). Indeed, they do not commune together as separate and divisible parts but rather interpenetrate in an indivisible oneness of life (something called perichoresis). Thus, the three would not be the three that they are without the one. The one and the three simply is in a way that is mutually defining. God in simplicity is indivisibly one and three, one in being three and three in being one.
In short, numbers in the form of human counting break down and explode at the border of trinitarian theology. Some kind of counting is involved, of course, but not one that is fully captured by counting as we know it. We count God in a way that is merely analogous to counting in the natural world. God is one in being and not in number. God is three in persons and not in number. If one tries to use counting as an absolute guide, one ends up with either an indistinct monotheism or a non-monotheistic tritheism, both of which would lack the perfection of the Triune God who is love in infinite fullness and freedom. Numbers are misleading when facing this mystery. As St. Basil wrote, “God is wholly beyond number.”[3] He rightly warns against being “carried away by an ignorant arithmetic” when it comes to understanding the Trinity.[4] Sage advice.
Frank D. Macchia
This helps paint a picture in describing the oneness of the Trinity. At least, it does for me.