5 Truths for Understanding the Trinity

By Dr. Bob Martin III
Published 3 years ago

Understanding the Trinity can be challenging and confusing. Why?

Because our triune God is eternal and infinite, and we are finite. How can we ever hope to completely understand the Trinity? We can’t.

The Trinity is a mystery, meaning we only know about it because it is revealed in the Bible. And while we can never completely comprehend the Trinity, we can understand many important things about our God. 

And understanding the Trinity can bring great joy and comfort to Christians. So let’s look at five truths for understanding the Trinity.


5 Truths for Understanding the Trinity One God exists as 3 distinct persons Trinity is Apprehended, not Comprehended Scripture Proves the Trinity An Analogy proves the Trinity is NOT Contradictory Christianity is Based on Understanding the Trinity



I.   Understanding the Trinity means One God Existing a Three Distinct Persons


1.   Christianity is monotheistic

Christians believe in only one God. That means that Christianity is a monotheistic religion. We worship only one eternal and infinite God. Jesus affirmed monotheism by quoting the Shema (Deut. 6:4) in Mark 12:29. “Hear, O Israel: The Lord our God, the Lord is one.” 


2.   The Christian God exists as a Trinity

But this one God exists as a Trinity. “Trinity” means “Tri-Unity” or “Three-in-One.” In other words, the Trinity means one God existing as three distinct persons. The three Persons are Father (Matt. 6:9,32), Son (John 17:5), and Holy Spirit (Acts 5:3-4).


3.   Skeptics Claim the Trinity is too Complicated and Contradictory

Understanding the Trinity may seem hard to grasp if you are a new Christian. And skeptics often criticize the Trinity for two reasons: 

  • First, the Trinity is too complicated 
  • Second, the Trinity is impossible to understand and is contradictory


II.   Understanding the Trinity Means Apprehending, not Comprehending

Before tackling those criticisms of the Trinity, we need to define two terms. These terms are two “secrets” to help us understand the Trinity. The two terms are “comprehend” and “apprehend.”

  1. “Comprehend” means that I understand the nature, significance, or meaning of it completely
  2. “Apprehend” means that I know it, at least in part, not wholly


1.   Understanding the Trinity is Like Putting the Ocean in a Hole on the Beach

How is knowing these two words helpful in understanding the Trinity? 

The famous painting “St. Augustine at the Seashore” represents a legend. It shows Augustine walking along a beach, lost in thought. He was puzzling over comprehensively understanding the Trinity. 

He saw a young boy running back and forth to the ocean filling his bucket. The boy then emptied his bucket of water into a hole he had dug in the sand. 

Augustine asked, “What are you doing.” The boy replied, “I’m trying to put the ocean into this hole.” 

Augustine realized that the boy’s task was futile. In the same way, his effort of trying to understand the infinite with a finite mind. No human could comprehend the Trinity in our tiny human minds. (1)


Painting of Saint Augustine at the Seashore by Alessandro Magnasco
Painting of Saint Augustine at the Seashore by Alessandro Magnasco, CC0, via Wikimedia Commons

2.   The Trinity can be Apprehended, not Comprehended

Of course, God is complicated! The Trinity is a Christian “mystery.” A mystery is something that an infinite and eternal God allows us to know about him only because it’s in the Bible. 

So comprehensively understanding the Trinity is impossible with our finite minds (Rom. 11:33–36). But complexity and incomprehension are not the same things! C. S. Lewis addressed this issue:

“If Christianity was something we were making up, of course, we could make it easier. But it is not. We cannot compete, in simplicity, with people who are inventing religions. How could we? We are dealing with fact. Of course, anyone can be simple if he has no facts to bother about” (2)

III.   Scripture Proves the Trinity

God revealed himself through the Bible (1 Cor. 2:10–11; Heb. 1:1–2). Because of the Bible, we can “apprehend” many things about the Trinity. 

We can apprehend that God exists as three distinct persons sharing one divine nature or essence (Matt. 3:16-17; John 10:30). Each member has a different role. For example:

  • God the Father planned salvation (John 3:16; Eph. 1:4)
  • The Son accomplished it on the cross (John 17:4; 19:30; Heb. 1:1-2) and the resurrection (Rom. 4:25; 1 Cor. 15:1-6)
  • The Holy Spirit applies it to the lives of the believers (John 3:5; Eph. 4:30) 


Here’s another example of a difference between the roles of the Son and the Holy Spirit:

  • The Son submits to the Father (1 Cor. 11:3; 15:28)
  • The Holy Spirit glorifies the Son (John 16:14)


The Trinity is an excellent example of why we must ground every Christian doctrine about God in Scripture (Ps. 19:7-14; 2 Tim. 3:14-17).

IV.   An Analogy that Proves the Trinity is NOT Contradictory

The critic says that the Trinity is contradictory. They are wrong. Scripture is clear that there is one God who exists as three Persons. The “three-in-one” of the Trinity is not a contradiction. 

Each number refers to a different aspect of the Trinity. 

  • The “three” refers to “Persons” (Father, Son, and Holy Spirit)
  • The one relates to his “divine nature.” 

These are different from each other. 

In understanding the Trinity, we can “apprehend” enough from Scripture and logic to show that the Trinity is not contradictory.

Is that confusing? Consider this diagram of a triangle:

Binmin diagram of a triangle showing the Trinity
Binmin diagram of a triangle showing the Trinity

The one triangle (God’s one divine nature) has three corners (Persons of the Trinity). The triangle’s three corners must be distinct, present, and simultaneous to each other for the geometric shape to be a triangle. If one corner is missing, the geometric shape is not a triangle. 

A triangle is a good illustration of the Trinity. But the triangle is finite, and God is infinite, so it is not a perfect illustration.

Distinguishing between three Persons and one divine nature resolves any misunderstanding. 

But what would be a contradiction? If we said the Trinity three and one in the exact same way! For example, it would be a contradiction to claim the Trinity is:

  • Three persons and one person 
  • Three divine natures and one divine nature. 

That would be contradictory.

A math analogy may also help. A critic might argue about God, “Doesn’t 1+1+1=3?” The Christian answers, “It would if our God were ‘tri-part,’ but he is not. He is ‘triune’ or represented by ‘1x1x1=1!’”

V.    Christianity is Based on Understanding the Trinity

The Trinity is so distinct from any other worldview that it should astonish you. Why? 

There is no way that the mystery of the Trinity is a human invention. The God of all things chose the Bible to share his incredible nature with us. And Scripture shows how he interacts with us and has accomplished our salvation. 

Why not spend some time reading through the Gospels or the New Testament lettersAnd see if you can uncover how the Father, the Son, and the Holy Spirit are at work. And then worship God with an even greater understanding of who he is. 



(1) Rengers, C. (2014). The 35 Doctors of the Church. Gastonia, NC: TAN Books.

(2) Lewis, C. S. (1953) Mere Christianity (p. 145). New York: Macmillan.


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