by Greg Lanier; THE GOSPEL COALITION; 12-11-20

Explaining the Christian doctrine of the Trinity isn’t easy. Analogies invariably flounder, and the risk of sliding into some sort of ancient heresy by accident is real. Just ask any ordination candidate how quickly the sharks circle if, due to nerves, you accidentally say, “God is made up of three persons.” Or ask any parent how they’d give an orthodox answer to their 5-year-old’s question, “Is God the same as Jesus?”

In addition to the conceptual difficulty, there are few, if any, large chunks of the New Testament that provide a full explanation of the Trinity. Skeptics are quick to point out that the word “Trinity” isn’t in the Bible. Even seasoned believers struggle with why God’s triunity isn’t more obvious. 

In other words, why did the apostolic authors not make things easier for us by doing more to explain the Trinity in detail—like Augustine’s De Trinitate—if it’s such a central confession?

Scripture Does Teach That God Is Triune

Before examining why the New Testament authors don’t do more, it’s essential to survey what they do reveal regarding the Trinity. In the New Testament, we see:

  • a full-orbed picture of a loving heavenly Father who is actively working redemption for his people;
  • the full divinity of the Son, Jesus Christ, in several key ways: conveying his pre-existence, establishing his unique divine sonship, applying Old Testament passages and concepts about God to him, describing early worship of him, and directly applying “God” to him;
  • the full personhood of the Holy Spirit, as a willing, acting, praying, life-creating, revealing personal agent (e.g., John 6:63Acts 20:28Rom. 8:26–271 Cor. 12:7–11), not an impersonal energy field or life-force; and
  • the mutual relations among the divine persons (e.g., Matt. 28:19Luke 10:21–22; 24:49John 20:22Acts 2:32–33Rom. 8:9–11).

Though the New Testament authors didn’t leave us with a systematic-theology textbook, the more you read Scripture, the more you see the triune God on its pages. You just have to have the “eyes to see.”

Trinity’s Hiddenness Explained

Nevertheless, it’s still true that there are few extended treatments of the Trinity in the New Testament.

Though the New Testament authors didn’t leave us with a systematic-theology textbook, the more you read Scripture, the more you see the triune God on its pages. 

Is this a problem? Is this an area where non-Christian opponents can slam dunk on orthodox believers? I don’t think so.

There are multiple cogent reasons why the New Testament might not be as direct or pronounced as we might want it to be.

1. Stretching Categories

The New Testament was written mostly by Jewish believers to a (frequently) Jewish audience, drawing on an Old Testament–saturated conceptual “encyclopedia.” And the chief confession inherited from ancient Israel is that of one true God, or monotheism (Deut. 6:4). The Old Testament features the Holy Spirit regularly and offers glimpses of the divine Son. But the full mystery of the triune God—that is, Trinitarian monotheism—isn’t fully unveiled until the coming of Jesus in the flesh and the outpouring of the Holy Spirit at Pentecost. 

Thus, explaining the Trinity in the early decades of the church to a (mostly) Jewish audience would’ve been like explaining a modern smartphone to a teenager in the early 1980s. The categories were there, but they needed stretching. Going too fast could (and did—see John 5:18) lead to confusion. So the New Testament authors appear to work primarily within the categories known to their audience in unveiling the Trinity gradually and often implicitly.

2. Primary Support

The primary objective of the new-covenant writings is to sustain the expansion of the Lord’s kingdom worldwide, to believing Jews and Gentiles (Matt. 28:19–20Luke 24:47Rom. 1:16–17Rev. 5:9–10). This shapes which topics do receive extensive explanations that we might otherwise expect for the Trinity. 

Four come to mind: 

These occupy the front lines of the mission of the church and, thus, receive more elaboration. 

A careful study of each of these discussions reveals how the New Testament authors support their arguments with Trinitarian thinking. For instance, Paul’s robust teaching on justification in Romans involves the quenching of the Father’s wrath (Rom. 1:18) through the propitiation offered by the Son (3:25), applied via heart-circumcision by the Spirit (2:29; 5:5). The New Testament authors may not have explicitly written about the Trinity, but they do employ Trinitarian thinking.

3. Showing Instead of Telling

Finally, in approaching the triune God as a personal reality instead of a doctrinal thesis, the New Testament authors are simply adopting the approach of their Old Testament forebears. 

Like any good director, the Old Testament often shows rather than tells. There are, in fact, several doctrines that are central to the Old Testament but receive few elaborate treatises, such as God’s election and decree, the total depravity of mankind, substitutionary atonement, the doctrine of Scripture, and Messianic expectation. Rather, these bedrock doctrines emerge cumulatively in the stories, laws, poetry, and prophecies of Israel. Moses could’ve written a 15-page, systematic-theologian–style “telling” of any one of these—but he instead engages in “showing” them through God’s self-revealing words and deeds in the life of Israel. 

The New Testament authors may not have explicitly written about the Trinity, but they do employ Trinitarian thinking. 

We should be thankful for this. Rather than having, say, a single chapter or set of verses that offer these bedrock truths in an open-shut fashion, we’re delighted to see them emerge everywhere, shaping everything in Scripture.

Turning to the New Testament, this approach is clearly evident for the Trinity. We might think we’d gain easy answers—or even a valid Trinitarian analogy!—if the apostles had only sat down to explain it once for all. But we’d lose the personal reality of our triune God everywhere, shaping everything.

As it stands, thankfully, we get to see the Trinity as our personal God, not just a doctrine—to savor him on every page, not just a few.

Greg Lanier (PhD, Cambridge) serves as associate professor of New Testament at Reformed Theological Seminary in Orlando. He is also an associate pastor at River Oaks Church (PCA). He lives in Oviedo with his wife, Kate, and their three daughters.