Why is the word “Trinity” not found in the Bible? Can the doctrine of the Trinity be drawn from Scripture itself?

These are questions I hear from people in nontrinitarian religions as well as Christians who believe in the Trinity but aren’t quite sure of its biblical basis. Given that the Trinity describes the nature of the God Christians worship, one might expect to see obvious trinitarian language in Scripture.

In fact, I recently received the following question about this topic on social media. Here’s the question followed by my response. I think this interaction can be helpful for Christians who engage in evangelism and interreligious (or counter cult) apologetics.

Question:
A religious person who recently knocked on my door said the Trinity doctrine was invented by the Christian church a couple centuries after Christ and has no biblical support. She said the word Trinity is not even a biblical term.

How can I effectively respond to this challenge?

My Response:
Thanks for your inquiry. I have had members of multiple non-trinitarian religious sects (Jehovah’s Witnesses, Christadelphians, Latter-Day Saints) say the same thing to me.

Here’s my way of responding:

Since the word “trinity” doesn’t appear in the Bible, some people may wonder whether the Trinity doctrine is simply an innovation of historic Christianity. The term trinity comes from the Latin trinitas. Church father Tertullian (c. A.D. 160–230) used this term when he wrote about “the trinity of the one Divinity—Father, Son, and Holy Spirit.”1

Some people are troubled that the word trinity doesn’t appear in the Bible. But the absence of this word in no way invalidates the doctrine. Many important biblical concepts are conveyed by terms not actually contained in the Bible—for example, terms like Bible, canon, and inerrancy. Nothing in the text prohibits the use of extrabiblical terms to express proper meaning.

Although the word trinity doesn’t appear, Scripture clearly reveals the doctrine of God’s tri-unity (three in one). Here is the Trinity doctrine in six biblically based propositions:2

1. There is one, and only one, God (1 Timothy 2:5).
2. The person of the Father is God (2 Peter 1:17).
3. The person of the Son is God (Titus 2:13).
4. The person of the Holy Spirit is God (Acts 5:3–4).
5. The Father, Son, and Holy Spirit are distinct and simultaneously distinguishable persons (Luke 3:22).
6. The three persons (Father or God; Son or Christ or Lord; and Holy Spirit or Spirit) are frequently listed together in a triadic pattern of unity and equality (John 14:26).

Now here’s the logical inference drawn from these passages:

Since there is only one God, and because the three persons (Father, Son, and Holy Spirit) are all called God, and since the three persons are distinct from each other, and because the three persons are all equal, then the three distinct and equal persons are the one God: Father, Son, and Holy Spirit.

Thus, the Trinity doctrine is not formally and explicitly taught in the Bible but it is derived implicitly from the content of Scripture. Though the apostles of Jesus were Jewish monotheists who believed strictly in one God, they nevertheless recognized that two other persons (the Son and the Holy Spirit) were revealed as God. All three persons possessed the qualities and prerogatives of deity. The apostles therefore modified traditional Jewish monotheism3 in light of the revelation concerning first the Son (Jesus Christ) and later the Holy Spirit.

The formal creedal doctrine of the Trinity took a few centuries to define and defend in light of various heresies that challenged it (modalism, tritheism, etc.).4 It was confirmed as church doctrine at the Council of Nicea (325). But the basis of the Trinity is found in the Bible.

Christian historian Mark Noll has written that “the ancient creeds became authoritative in the early centuries because they were thoroughly, profoundly, comprehensively, and passionately rooted in Scripture.”5

Takeaways

• The word Trinity is not in the Bible but the truth that God is three and one is biblical. 
• The doctrine of the Trinity is not presented explicitly in Scripture but it is clearly derived implicitly. 
• The formal creedal doctrine of the Trinity did take a few centuries to define and defend.

Resources

• For more on a biblical treatment of the Trinity, see Peter Toon, Our Triune God: A Biblical Portrayal of the Trinity.
• For more on the history of the Trinity, see Robert Letham, The Holy Trinity: In Scripture, History, Theology, and Worship.
• For more on the general doctrine of the Trinity, see “How Can God Be Three and One” in Kenneth Richard Samples, Without a Doubt: Answering the 20 Toughest Faith Questions, chapter 5.
• For a discussion of the Trinity as a divine mystery, see “Aren’t Theological Mysteries Just Logical Contradictions?” in Kenneth Richard Samples, Christianity Cross-Examined: Is It Rational, Relevant, and Good?, chapter 5.

Check out more from Reasons to Believe @Reasons.org

Endnotes

1. Tertullian, De Pudicitia, The Tertullian Project, 21, updated June 13, 2023.

2. For a fuller outline of the Trinity doctrine, see Kenneth Richard Samples, A World of Difference: Putting Christian Truth-Claims to the Worldview Test (Grand Rapids, MI: Baker Books, 2007), 131–132.

3. New Testament and ancient historian Larry W. Hurtado describes the primitive Jewish-Christian church’s view of Jesus as an extension of Yahweh as a mutation within monotheistic Judaism. See Larry W. Hurtado, How on Earth Did Jesus Become a God? Historical Questions about  Earliest Devotion to Jesus (Grand Rapids, MI: Eerdmans, 2005). A similar mutation would take place in also seeing the Holy Spirit as an extension of Yahweh.

4. See “Trinitarian Heresies,” monergism.com, accessed July 27, 2023.

5. Mark A. Noll, Jesus Christ and the Life of the Mind (Grand Rapids, MI: Eerdmans, 2011), 2.