Christian Theology: The Trinity


Islam affirms the oneness of God every time a Muslim utters the "witness": "There is no God but God, and Muhammad is his prophet."  From earliest times, Jewish tradition also affirmed that "the Lord our God, the Lord is one" (Deuteronomy 6:4, the "Shema" which is recited in daily Jewish spirituality).  Such monotheism was a radical departure from the polytheism of ancient cultures.

Christians believe in the unity and singularity of God as well.  Jesus clearly stated that "the Lord our God, the Lord is one" (Mark 12:29).  The New Testament tells us to "believe that there is one God" (James 2:19), for "there is no God but one" (1 Corinthians 8:4).

At the same time, the New Testament clearly teaches that Jesus is God.  Jesus claimed to be eternal: "I tell you the truth, before Abraham was born, I am!" (John 8:58).  The first believers affirmed his eternal nature: "In the beginning was the Word, and the Word was with God, and the Word was God.  He was with God in the beginning" (John 1:1-2).  Paul could describe Jesus as "God over all, forever praised" (Romans 9:5).  They were waiting for "the blessed hope—the glorious appearing of our great God and Savior, Jesus Christ" (Titus 2:13).

The disciples watched Jesus calm stormy seas, heal blind eyes, and raise the dead.  They knew that he has been resurrected and ascended into heaven.  Everything they had been taught to believe about God the Father, they came to believe about God the Son.

And the first Christians experienced the Holy Spirit as divine as well.  Peter warned Ananias that by lying to the Holy Spirit, he had lied to "God" (Acts 5:3, 4).  Paul could speak of "the Lord" and "the Spirit" as synonymous (cf. 2 Corinthians 3:17-18).

Yet these three Persons were independent in action.  For instance, at Jesus' baptism, the Father spoke from heaven as the Son came up from the water and the Spirit descended (Matt. 3:16-17).

Christians worship one God in three persons.  How can we understand this doctrine?

What is the "Trinity"?

It has been said that if the mind were simple enough for us to understand it, we would be too simple to understand it.  Likewise, if God were simple enough for my finite, fallen mind to understand him, he would not be God.  How does a mother explain marriage to her five year old daughter?  How does a mathematician explain calculus to his third grade son?

Yet we try.  We sing as though we understood the words, "Holy, Holy, Holy!  Lord God Almighty . . . God in three Persons, blessed Trinity."  I speak the same words over new believers which were recited over me in the baptismal waters, and over other Christians for twenty centuries: "I baptize you in the name of the Father, and of the Son, and of the Holy Spirit."  Why?  What is the Trinity?  And why is understanding it so essential?

A brief history of God

The first biblical reference to God starts the mystery: "In the beginning God created the heavens and the earth" (Genesis 1:1).  The Hebrew term here translated "God" is Elohim.  The "im" is how the Hebrew language makes a word plural, like putting "s" on the end of a word in English.  Thus one could translate the word "Gods" (though some Hebrew scholars believe that the plurality points more to God's majesty than his number).

However, the following Hebrew verb "created" requires a singular noun, indicating that its subject is one rather than many.  In English we would say "they create" but "he creates"; the latter is the idea of Genesis 1:1.  So, in "God created" we have our start into the mystery that is the nature of God.

From earliest times, the Jewish tradition has affirmed that "the Lord our God, the Lord is one."  Christians agreed, but came to know Jesus and the Spirit as divine as well.  There is no indication that apostolic Christians struggled with the logic of their experience of God.  Paul could pray for the Corinthians, "May the grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit, be with you all" (2 Corinthians 13:14).  They knew God to be one, but they experienced him as three persons.  This logical contradiction did not trouble them, for they were more pragmatic than speculative.  They needed no words such as "Trinity" or theological formulations to explain their faith.  But matters would quickly change.

The problem of God

As Christianity spread beyond its Jewish roots, it encountered a world view steeped in logic and rationalism.  Aristotle had taught the Western world that non-contradiction is the test for all truth.  Something cannot be one and three at the same time.  So how can the Christian doctrine of God be reasonable?

The word "Trinity" is not found in the Bible.  (Neither is "monotheism," though we believe in one God.)  The term arose in response to the problem of the unity of God—he is one God, but he acts as Father, Son, and Spirit.  

This fact was apparently not a problem for the biblical writers, thus the word "trinity" and doctrinal argument are not found explicitly in Scripture.  The first Christians knew God to be one, but they experienced him as three persons.  They needed no words such as "Trinity" or theological formulations to explain their faith.  But matters would quickly change.

As Christianity spread beyond its Jewish roots, it encountered a world view steeped in logic and rationalism.  Aristotle had taught the Western world that non-contradiction is the test for all truth.  Something cannot be one and three at the same time.  So how can the Christian doctrine of God be reasonable?

The earliest answers to the question resolved the logical tension, but created problems greater than the one they "solved."  Some made the Son and the Spirit less divine than the Father, an approach known as subordinationism."  By this formulation, Jesus is not Lord and the Holy Spirit who makes us Christians (cf. Ro. 8:9) is not fully God.  Others taught that God shifts from being Father (Old Testament) to Son (Gospels) to Spirit (Acts to Revelation), an approach known as "modalism."  This strategy cannot explain the baptism of Jesus, the work of the Son (Jn. 1:3-4) and the Spirit (Gen. 1:2) in creation, or the presence of the Spirit throughout the Old Testament (cf. Psalm 51:11).  "Dynamic monarchians" taught that divine power descended upon Jesus, so that he was not himself divine.  

At the Councils of Nicaea (AD 325) and Constantinople (AD 381), the orthodox Church declared all such formulations to be heretical, and affirmed that the Son and Spirit are of the same "essence" as the Father.  "God in three Persons" catches the sense of their approach.  And so theologians developed the doctrine of the "Trinity," from the Latin word trinitas, "three" or "triad."  To be specific, a theologian named Tertullian (early third century) is usually credited as the first to use the word with reference to the three Persons of God.

Commitment to a God whose essence transcends our logical comprehension is a problem for some in our rationalistic culture.  We like our faith to make sense.  We may not understand why a ship floats or an airplane stays in the air, but we know that someone does.  We'd have a hard time taking medicine no one understands, expecting effects no one can explain.

But we'd best get used to it.  The more we learn about the universe, the more incomprehensible it becomes.  Physicians do not understand how the mind works, or even if there is such a thing as the "mind."  We assume the category of time, but none of us can define it without contradiction.

So it is with the major doctrines of Christian faith.  Is God three or one?  Is Jesus fully God or fully human?  Does God know the future or do we have freedom?  Is the Bible divinely inspired or humanly written?  The answer to each question is the same: yes.

The divinity of Jesus

Muslims, Jews, and Christians hold in common our belief that there is a God of the universe.  When we speak of the "Father," we are on familiar footing with other monotheistic faiths.  But when we elevate the Son and the Spirit to divine status, we create the kind of tension which leads to confusion and rejection.  So let's take a moment to examine the divinity of the Second and Third members of the Godhead.

"Jesus is Lord" is the central affirmation of the Christian faith.  Its Greek original is found scrawled on walls in the Roman catacombs and at the heart of the most ancient formulations of faith.  When the Empire forced Christians to say "Caesar is Lord" or die, believers by the multiplied thousands chose to die.  If presented the same option, we should make the same choice.  Why?

Did Jesus claim to be God?

In recent years it has become popular to claim that Jesus of Nazareth saw himself only as a religious teacher, and that the Church deified him over the centuries.  Not according to the eyewitnesses.  When Jesus stood on trial for his life, the high priest challenged him: "I charge you under oath by the living God: Tell us if you are the Christ, the Son of God" (Mt. 26:63).  His answer sealed his fate: "Yes, it is as you say" (v. 64).  He clearly claimed to be God.

And his first followers accepted his claim to be true.  Peter and the other apostles refused to stop preaching that Jesus is Lord, even when threatened with their lives (cf. Ac. 5:29-32).  Each but John was martyred for his faith in Christ, and John was exiled to the prison island of Patmos for preaching the Lordship of Jesus.  Billions of people across twenty centuries have accepted their truth claims and followed their Lord as God.

How do we know he was right?

Here is the rope from which Christianity swings: "If there is no resurrection of the dead, then not even Christ has been raised.  And if Christ has not been raised, our preaching is useless and so is your faith.  More than that, we are then found to be false witnesses about God, for we have testified about God that he raised Christ from the dead" (1 Cor. 15:13-15).  Before Easter, the disciples assumed their leader was dead and gone.  After that day, they were transfused with divine courage and set about winning the world to Jesus.  The resurrection was the basis for their commitment to Christ as Lord.  It is ours as well.

We know Jesus existed, and was crucified at the hands of Pontius Pilate.  We know that the first Christians believed him to be raised from the dead (cf. the letter of Pliny the Younger, the descriptions of Josephus).  But believing doesn't make it so.  Is there objective evidence for their faith in a risen Savior?

David Hume was an 18th-century Scottish philosopher, known today as the "Father of Skepticism."  He made it his life's work to debunk assumptions which he considered to be unprovable, among them the veracity of miracles.  He argued for six criteria by which we should judge those who claim to have witnessed a miracle: they should be numerous, intelligent, educated, of unquestioned integrity, willing to undergo severe loss if proven wrong, and their claims should be capable of easy validation (David Hume, An Enquiry Concerning Human Understanding, 2d ed. [LaSalle, Illinois: Open Court, 1966] 128-9).  Each is appropriate for determining the truthfulness of a witness.  How do the eyewitnesses of the risen Christ fare by such standards?

They were numerous: over 500 saw the resurrected Lord (1 Cor. 15:6).  They were intelligent and well-educated, as the literature they produced makes clear (the Acts 4:13 claim that they were "unschooled, ordinary men" meant only that they had not attended rabbinic schools).  Paul was in fact trained by Gamaliel, the finest scholar in Judaism (Ac. 22:3).  They were men and women of unquestioned integrity, clearly willing to undergo severe loss, as proven by their martyrdoms.  And their claims were easily validated, as witnessed by the empty tomb (cf. Ac. 26:26, "this thing was not done in a corner").

So the witnesses were credible.  What of the objective evidence for their claims?  It is a fact of history that Jesus of Nazareth was crucified and buried, and that on the third day his tomb was found empty.  Skeptics have struggled to explain the empty tomb ever since.

Three strategies center on theft.  The first was to claim that while the guards slept, the disciples stole the body (Mt. 28:11-15).  How would sleeping guards know the identity of such thieves?  How could the disciples convince 500 people that the corpse was alive?  And why would these disciples then die for what they knew to be a lie?  A second approach claims that the women stole the body.  How would they overpower the guards?  How would they make a corpse look alive?  Why would they suffer and die for such fabrication?  A third explanation is that the authorities stole the body.  When the misguided disciples found an empty tomb, they announced a risen Lord.  But why would the authorities steal the body they had positioned guards to watch?  And when the Christians began preaching the resurrection, wouldn't they quickly produce the corpse?

A fourth approach is the wrong tomb theory—the grief-stricken women and apostles went to the wrong tomb, found it empty, and began announcing Easter.  But the women saw where he was buried (Mt. 27:61); Joseph of Arimathea would have corrected the error (Mt. 27:57-61); and the authorities would have gone to the correct tomb and produced the corpse.

A fifth strategy is the "swoon theory"—Jesus did not actually die on the cross.  He or his followers bribed the medical examiner to pronounce him dead, then he revived in the tomb and appeared to be resurrected.  But how could he survive burial clothes which cut off all air?  How could he shove aside the stone and overpower the guards?  How could he appear through walls (Jn. 20:19, 26) and ascend to heaven (Ac. 1:9)?

There is only one reasonable explanation for the empty tomb, the changed lives of the disciples, and the overnight explosion of the Christian movement upon the world stage: Jesus Christ rose from the dead.  He is therefore the person he claimed to be: our Lord and God.  Trusting him is not a leap into the dark, but into the light.  When you jump, crucified hands will catch you and never let you go (Jn. 10:28).

The divinity of the Holy Spirit

The Holy Spirit is the third member of the Trinity, as fully divine as the Father and the Son.  He is a person, deserving of our respect and gratitude.  The Holy Spirit has all the distinctive characteristics of personality: knowledge (1 Cor. 2:10-11), will (1 Cor. 12:11), and feeling or emotion (Ro. 15:30).  He performs acts which only a person can perform: he searches (1 Cor. 2:10), speaks (Rev. 2:7), cries (Galatians 4:6), prays (Ro. 8:26), testifies (Jn. 15:26), teaches (Jn 14:26), leads (Ro. 8;24), and commands (Ac. 16:6, 7).  He is treated as only a person can be treated: he is grieved and rebelled against (Isaiah 63:10; Ephesians 4:30), insulted (Hebrews 10:29), and blasphemed (Mt. 12:31, 32).

The Holy Spirit is given each of the four distinctly divine attributes: eternity (Heb. 9:14), omnipresence (Ps. 139:7-10), omniscience (1 Cor. 2:10, 11), and omnipotence (Lk 1:35).  He performs each of the three distinctly divine works: creation (Job 33:4; Ps. 104:30; Gen. 1:1-3), impartation of life (Jn. 6:63; Gen. 2:7), and authorship of prophecy (2 Peter 1:21).

Exodus 16:7 says that the people "grumbled" against God; Hebrews 3:7 quotes the Holy Spirit's statement that such complains were made against him.  The name of the Holy Spirit is coupled with that of God (1 Cor. 12:4-6; Mt. 28:19-20; 2 Cor. 13:14).  The Holy Spirit is called God (Ac. 5:3, 4).

And yet the Holy Spirit is distinct from the Father and the Son (Lk 3:21, 22; Mt. 28:19; Jn. 16:7).  He is sent by the Father in the name of the Son (Jn 14:26; 15:26), speaks only what he hears from the Father (Jn 16:13), and seeks only to glorify God (Jn 16:14).

In every sense, the Holy Spirit is God.  We can "solve" the problem of the Trinity by devaluing the Son and the Spirit, but we lose far more than we gain.  We forfeit the divine Savior whose death paid for our sins, and the divine Person who brings salvation to our souls.  I would rather live with the mystery of God's nature than give up the relationship with him which that nature makes possible.

How can we describe the Trinity?

Over the centuries, theologians have tried to explain the Trinity in a variety of ways.  One early analogy likened the concept to an egg, with its shell, white, and yolk.  Another compared it to a tree, with its roots, branches, and leaves.  The problem with both analogies is that their elements are not all made of the same substance, while the Father, Son, and Spirit are all equally divine.

Some compare the Trinity to water, since it can exist as ice, liquid, or gas while remaining H2O.  However, it cannot do all three at the same time.  (This analogy can suggest a kind of modalism.)  Others liken the Trinity to a corporate partnership of three, with specific responsibilities for each; but this analogy does not fully acknowledge the unity of the Trinity.

Still others suggest that the Trinity is like a three-sided building.  When viewed from the ground, each side appears to be individual; but when viewed from overhead, their unity is apparent.  However, the three Persons of the Trinity function more independently than the sides of a building.

An approach growing in popularity likens the Trinity to a kind of dance in which the three Persons move in interdependent, dynamic mutuality and unity.  But this approach does not acknowledge fully the fact that all three are of the same divine essence.

The best analogy I have seen was suggested during a theology class I was teaching recently in Bangladesh.  We were meeting on the third floor of a building.  One of the students observed that this floor was all we could see, though there were two others below us.  When you're standing on one of the floors, it's hard to see the other two, yet all three exist.  And all three are made of the same material and form one building.  So it is with the trinitarian God: Father, Son and Spirit are all divine, each an individual person, but all three the one God.

Once we have explored all the rational explanations, we are left with mystery.  We should not be able to comprehend the divine nature of the one true God.  All our analogies fall short of his miraculous, supernatural essence.  They may help clarify his nature, but they cannot capture it.  As we noted earlier, if we can understand fully the essence of God, he would not be God.

Why does the doctrine of the Trinity matter today?

The doctrine of the Trinity is crucial today for at least four reasons.  First, it affirms the divinity of the Son and the Spirit in a time when both are challenged and even rejected.  As we will see when we explore the doctrine of Christ, there have been numerous attacks on the divinity of Jesus over recent years.  Some alternate spiritual movements such as Jehovah's Witnesses depreciate or deny the deity of the Spirit as well.  The doctrine of the Trinity affirms the essential divine nature of each Person.

Second, the doctrine can help us to pray.  Many Christians direct their prayers to the Member of the Trinity most appropriate for their request or praise.  They address the Father as the ground and source of life.  They praise the Son for his atoning sacrifice and love.  They speak to the Spirit in gratitude for his work in bringing us to salvation and spiritual growth.  They ask the Father for his protection and forgiveness, the Son for his intercession and help, and the Spirit for his guidance and power.  Approaching God in Trinitarian ways can strengthen our prayer lives.

Third, the doctrine reminds us of the importance of community.  God dwells forever in relationship with himself.  In the same way, Christianity cannot be done alone.  The images of the Church in the New Testament are all collective--a body with many members, a vine with many branches.  Unity and community are vital elements of spiritual experience and growth.

Last, the Trinity reinforces the fact that God is love (1 John 4:8).  God has existed in love before time began and the first human was created, for the Members of the Trinity cohabit in a love relationship with each other.  As the Persons of the Trinity love each other, so they love us.  Now we are included in their loving embrace and eternal unity.


We've discussed briefly the trinitarian nature of God and the divinity of the Son and the Spirit.  The practical outcome of such a brief survey is simply this: we are each to give ourselves every day to the Spirit.  We are to yield the morning as it begins and the day before it starts.  We are to seek his wisdom and direction for every step and every decision.  We are to be led by his grace in every moment.  And as we practice his presence in our lives, we experience the abundant life which Jesus came to give us all (Jn. 10:10).

One of my favorite stories concerns a father who arrived home after work and was greeted by his two small daughters.  The older girl got to him just as he stepped onto the sidewalk leading from the driveway, with a hedge on either side.  She threw her arms around her father's legs.  The younger sister then arrived.  Her older sister was in front of her, hedges on both sides, and she couldn't get to her father.  Her big sister taunted her, "Ha, ha, ha, I've got all of Daddy there is."

The wise father then reached over his older daughter, picked up the younger sister, and held her in his arms.  The younger girl then said to the older, "Ha, ha, ha, Daddy's got all of me there is."

You have all of the Father there is.  Does he have all of you today?