The Holy Trinity (1620) by Henrik van Balen (1575-1632), oil on panel, Sint-Jacobskerk, Antwerp
The doctrine of the Trinity teaches that there is only one God who exists as three persons: Father, Son, and Holy Spirit. (If you prefer a gender-neutral formulation, you could use “Parent, Child, and Comforter” instead.) Not three gods. Not three personalities. One God, three Persons. All three Persons are God: Father, Son, and Holy Spirit. They have always been God, and will always be God. Moreover, the Father is not Son, the Son is not the Spirit, and the Spirit is not the Father. They are three distinct Persons in one Godhead. Sounds complicated, even illogical. Theologians call it a “mystery”—not in the sense of a puzzle to be solved, but a truth that was formerly hidden but has now been revealed.
The Trinity is perhaps the most important and unique teaching in Christianity and it’s central to Christian worship. Despite its importance, the term “Trinity” doesn’t appear in the Bible and the doctrine is explicitly stated nowhere in scripture. It is, however, present in embryo in a number of passages. One of the most interesting is the baptismal formula of Matthew 28:19, “baptizing them in the name of the Father, and of the Son, and of the Holy Spirit.” Nowhere else in the New Testament do we find a Trinitarian formula associated with baptism, not even in the parallel passages in Mark and Luke. In the Book of Acts the apostles baptized “in the name of Jesus” only (Acts 8:12, 19:5).
Some scholars have questioned the authenticity of the triune formula, because it’s unique to Matthew and sounds too theological for Jesus’ earthly ministry. This supposed anachronism has caused some to conclude that Matthew’s triune formula was added to the Bible later. However, the words “in the name of the Father, and of the Son, and of the Holy Spirit” in Matthew 28:19 are found in all existing biblical manuscripts, making it improbable that they were added long after the Gospel was written (Tasker, Matthew, 275). All three Persons of the Trinity were present at Jesus’ own baptism (Matt. 3:16, 17), so it isn’t surprising that the Lord would mention all three in a baptismal formula.
Even if the Trinitarian formula were from a later period, which I doubt, it wouldn’t disturb me. The fact that the doctrine of the Trinity isn’t explicitly stated in the New Testament doesn’t bother me either, any more than it bothers me that an acorn doesn’t have a trunk, branches, and leaves. Theology matures and changes as the church grows older and faces new challenges. As in biology, growth in theology is generally a good thing, though it can go wrong sometimes.
Illustrations for the Trinity are all flawed, whether its three states of water (liquid, ice, steam) or three roles of a person (father, husband, worker) or three parts of an object (three leaves of a clover). The Trinity is a doctrine “we cannot fully comprehend, although we can apprehend.” (Oden, The Living God, 224). Dogs cannot use or fully comprehend human speech, but they can apprehend certain tones and commands. They have limited comprehension, because they’re dogs. Humans are the same way when it comes to divine truth. We can only understand so much before reaching the end of our intellectual ability.
When we come to the limits of reason, we must rely on faith to help us accept what is hard to understand.