The Heart of It All: The Trinity (Part 1)

May 17, 2011

by Peter Amsterdam

Audio length: 20:20

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(For an introduction and explanation regarding this series overall, please see The Heart of It All: Introduction.)

In the first two articles of The Heart of It All series we saw that the New Testament reveals the deity of Jesus, that Jesus is God.

In reading the verses quoted in those sections, it’s clear that besides Jesus—God the Son—there is also the Father who is God, as Jesus prays to the Father, does the Father’s will, etc. The Bible also speaks of the Holy Spirit, who is God as well.

One God, three Persons

For the uninitiated, the impression could be that Christianity believes in three Gods—the Father, the Son, and the Holy Spirit. But that’s not the case. Christians believe that there is only one God. The doctrine that explains the concept of how the Father, Son, and Holy Spirit are one God is called the doctrine of the Trinity.

This doctrine explains that God has always existed as three persons in one being. This is very different from humans, as we exist as one person in one being—we are uni-personal. God exists as a tri-personal being—three persons, each distinct from the other, the Father, the Son, and the Holy Spirit—and yet is one being. While God is tri-personal, each of the persons is fully God, having all of the attributes and the complete essence of God. (For more on the attributes of God, see The Heart of It All series "The Nature and Character of God.")

Theologian Louis Berkhof wrote that the word “person” is an imperfect expression of the idea, because today it denotes a separate rational and moral individual. Christian philosopher Kenneth Samples concurs. “The three persons of the Trinity should not be understood as three ‘parts’ or ‘fractions’ of God. Each person is fully divine and equally possesses all of God’s being … the term ‘person’ in reference to the Trinity is used in a unique sense and should not be understood to refer to a separate entity or being, for this would divide the divine essence.”[1]

Our experience as human beings is that where you have a person, you also have a distinct individual essence. Every person we know is a distinct and separate entity, in whom human nature is individualized. But in God there aren’t three individuals alongside of, and separate from, one another. Rather, there is one divine being, one essence, with three personal self-distinctions.

Another way to put it is that in the being of God, the three distinct Persons have an interpersonal relationship. They communicate and have interaction with one another. In Scripture you have the Father addressing the Son as You:

You are My beloved Son; with You I am well pleased.[2]

You also have the Son referring to the Father as He, and showing communication between them:

For the Father loves the Son and shows Him all that He Himself is doing.[3]

You have an example of the Son calling Himself I, and differentiating Himself from both the Father and the Holy Spirit:

But when the Helper comes, whom I will send to you from the Father, the Spirit of truth, who proceeds from the Father, He will bear witness about Me.[4]

Thus God, who is tri-personal, has interaction and a personal relationship between the different Persons within the being of God.

I particularly like how Christian philosopher and author William Lane Craig describes the Trinity in one of his lectures:

Just like I, as a being, support one center of self-consciousness, which I call I or me, God is a being that supports three centers of self-consciousness. God is a being with three centers of self-consciousness, three I’s or selves. Thus God’s being supports three persons.[5]

The concept of three persons in one God was not something that was explicitly expressed in the Old Testament, though there are Old Testament verses which infer that there is more than one person in God. The understanding of the three persons in one God became clearer in the New Testament because of the life, death, and resurrection of Jesus, and the outpouring of the Holy Spirit on the believers. The followers of Jesus came to understand that He was God, but was distinct from the Father, and that the Holy Spirit was also God, but was distinct from the Father and the Son. So it was in New Testament times that the truth of the Trinity unfolded and was revealed.

Developing and articulating the understanding of this doctrine was done progressively in early church history, and that will be more thoroughly explained in the next article on this topic. Although the word Trinity doesn’t appear within the biblical text, Scripture reveals the doctrine, and the word Trinity conveys the concept.

Concept of the Trinity in the Old Testament

While the Old Testament does not reveal that God is a triune being, some Old Testament passages do speak in a manner that suggests that God is more than one Person.

Then God said, “Let us make man in our image, after our likeness.”[6]

Then the Lord God said, “Behold, the man has become like one of us in knowing good and evil.”[7]

“Come, let us go down and there confuse their language, so that they may not understand one another’s speech.”[8]

And I heard the voice of the Lord saying, “Whom shall I send, and who will go for us?”[9]

In these next verses, also from the Old Testament, the speaker is either God the Father or God the Son, and they make reference to each other or to the Spirit, again inferring different persons in the Godhead.

Who has ascended to heaven and come down? Who has gathered the wind in His fists? Who has wrapped up the waters in a garment? Who has established all the ends of the earth? What is His name, and what is His Son's name? Surely you know![10]

Do homage to the Son, that He not become angry, and you perish in the way, For His wrath may soon be kindled. How blessed are all who take refuge in Him![11]

“Draw near to Me, hear this: from the beginning I have not spoken in secret, from the time it came to be I have been there.” And now the Lord God has sent Me, and His Spirit.[12]

The Spirit of the Lord God is upon Me, because the Lord has anointed Me to bring good news to the poor.[13]

One of the great scriptures from Torah—the five books of Moses, corresponding to the first five books of the Christian Old Testament—which is fundamental to Judaism is:

Hear, O Israel: The Lord our God is one Lord.[14]

Judaism is a monotheistic religion which believes there is only one God. This belief was by and large unique to Israel in the time of the Old Testament, as virtually all cultures in the region were polytheistic, including all of Israel’s neighbors throughout history until the time of Christ.

Christianity is monotheistic as well. Christians believe there is only one God, and affirm this same Bible verse, “the Lord our God is one Lord.” However, unlike Judaism, Christians believe in the tri-personal God, three persons in one Being.

Augustine and Trinity logic

Augustine (354–430 AD), one of the greatest figures of Christianity in the western part of the Roman Empire, and considered the most important Christian writer next to the Apostle Paul, summarized the fundamental logic of the Trinity in seven short statements. These statements are:

  1. The Father is God.
  2. The Son is God.
  3. The Holy Spirit is God.
  4. The Father is not the Son.
  5. The Son is not the Holy Spirit.
  6. The Holy Spirit is not the Father.
  7. There is only one God.

The first three statements express that each member of the Trinity is God. The second three statements assert that each member of the Trinity is distinct one from another. The last statement declares that there is only one God.

While all of this may be difficult to fully understand, if we build from Augustine’s foundational seven statements, it’s plain to see that the Bible lays out the case for the Trinity—three distinct persons as one God.

The Father is God.

The following verses express that the Father is God:

You are my Father, my God, and the Rock of my salvation.[15]

Thou, O Lord, art our Father, our Redeemer; Thy name is from everlasting.[16]

After this manner therefore pray ye: Our Father which art in heaven, hallowed be Thy name.[17]

One God and Father of all, who is above all, and through all, and in you all.[18]

He received from God the Father honour and glory, when there came such a voice to Him from the excellent glory, This is My beloved Son, in whom I am well pleased.[19]

John chapter 17 is a prayer that Jesus prays to the Father, showing that He considered the Father as God.

The Son is God.

The following verses express that Jesus is God:

In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. All things were made through Him, and without Him was not any thing made that was made.[20]

Jesus said unto them, Verily, verily, I say unto you, Before Abraham was, I am.[21]

He [Jesus/Son] is the image of the invisible God, the firstborn over all creation. For by Him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things were created by Him and for Him. He is before all things, and in Him all things hold together. And He is the head of the body, the church; He is the beginning and the firstborn from among the dead, so that in everything He might have the supremacy. For God was pleased to have all His fullness dwell in Him, and through Him to reconcile to Himself all things, whether things on earth or things in heaven, by making peace through His blood, shed on the cross.[22]

For in Christ all the fullness of the Deity lives in bodily form.[23]

In the past God spoke to our forefathers through the prophets at many times and in various ways, but in these last days He has spoken to us by His Son, whom He appointed heir of all things, and through whom He made the universe. The Son is the radiance of God’s glory and the exact representation of His being, sustaining all things by His powerful word. After He had provided purification for sins, He sat down at the right hand of the Majesty in heaven.[24]

No one has seen God at any time; the only begotten God who is in the bosom of the Father, He has explained Him.[25]

The Holy Spirit is God.

The following verses express that the Holy Spirit is God:

In the book of Acts, Peter says that lying to the Holy Spirit is lying to God.

Peter said, “Ananias, how is it that Satan has so filled your heart that you have lied to the Holy Spirit and have kept for yourself some of the money you received for the land? Didn’t it belong to you before it was sold? And after it was sold, wasn’t the money at your disposal? What made you think of doing such a thing? You have not lied to men but to God.”[26]

Psalm 139 shows that the Holy Spirit is omnipresent, something that only God is.

Where shall I go from Your Spirit? Or where shall I flee from Your presence? If I ascend to heaven, You are there! If I make my bed in Sheol, You are there! If I take the wings of the morning and dwell in the uttermost parts of the sea, even there Your hand shall lead me, and Your right hand shall hold me.[27]

1 Corinthians 2 shows the Holy Spirit as omniscient, knowing everything, one of the attributes of God alone.

These things God has revealed to us through the Spirit. For the Spirit searches everything, even the depths of God. For who knows a person’s thoughts except the spirit of that person, which is in him? So also no one comprehends the thoughts of God except the Spirit of God.[28]

This verse states that as a human is the only one who knows what goes on in his mind and spirit—that his inner thoughts are known only to him—similarly the inner thoughts of God are only known to God Himself, thus showing that the Spirit of God is God, since the Spirit of God comprehends the thoughts of God.

This next verse shows that the Holy Spirit was present from before the creation of the world, and played a role in some manner:

Now the earth was formless and empty, darkness was over the surface of the deep, and the Spirit of God was hovering over the waters.[29]

The following verses show the Holy Spirit working along with Jesus in our lives as Christians.

You were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and by the Spirit of our God.[30]

Jesus told His disciples that:

The Counselor, the Holy Spirit, whom the Father will send in My name, will teach you all things and will remind you of everything I have said to you.[31]

Three distinct Persons

In 2 Corinthians, Paul lists the three persons of the Trinity in a manner that shows they are distinct from one another.

The grace of the Lord Jesus Christ and the love of God and the fellowship of the Holy Spirit be with you all.[32]

Jesus, just before ascending into heaven, commands the disciples to baptize in the name of each person of the Trinity, thus showing He saw them all as equal, all as God.

Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit.[33]

The way the New Testament authors refer to Father, Son, and Holy Spirit shows their distinctness—that they are different from one another and that they interact in ways that show they are not the same person. For example, Jesus asks the Father to send the Spirit, which shows three different Persons interacting together.

I will ask the Father, and He will give you another Helper, to be with you forever, even the Spirit of truth.[34]

All things have been handed over to Me by My Father, and no one knows the Son except the Father, and no one knows the Father except the Son and anyone to whom the Son chooses to reveal Him.[35]

When Jesus was baptized, immediately He went up from the water, and behold, the heavens were opened to Him, and He saw the Spirit of God descending like a dove and coming to rest on Him; and behold, a voice from heaven said, “This is My beloved Son, with whom I am well pleased.”[36]

Now this He said about the Spirit, whom those who believed in Him were to receive, for as yet the Spirit had not been given, because Jesus was not yet glorified.[37]

These verses help to show that the Father, Son, and Holy Spirit are distinct one from another.

One God

Augustine’s last statement is “There is one God.”

Both the Old and New Testaments, as well as Jesus Himself, affirm that there is only one God.

One of the scribes came up and heard them disputing with one another, and seeing that He answered them well, asked Him, “Which commandment is the most important of all?” Jesus answered, “The most important is, ‘Hear, O Israel: The Lord our God, the Lord is one.’”[38]

That all the peoples of the earth may know that the Lord is God; there is no other.[39]

I am the Lord, and there is no other, besides Me there is no god.[40]

There is no other god besides Me, a righteous God and a Savior; there is none besides Me. … Turn to Me and be saved, all the ends of the earth! For I am God, and there is no other.[41]

Is God the God of Jews only? Is He not the God of Gentiles also? Yes, of Gentiles also, since God is one—who will justify the circumcised by faith and the uncircumcised through faith.[42]

Therefore, as to the eating of food offered to idols, we know that “an idol has no real existence,” and that “there is no God but one.”[43]

You believe that God is one; you do well. Even the demons believe—and shudder![44]

Augustine’s statements, which are based on Scripture, make it clear that God is three persons—the Father, the Son, and the Holy Spirit—that they are distinct from each other, and that there is only one God.

While his statements may explain the fundamental logic of the Trinity, that doesn’t make it understandable. In truth, the concept of Father, Son, and Holy Spirit being one God is impossible for us as humans to completely understand. We have nothing like it in our world. It’s completely beyond our experience. That might be disconcerting, but it’s also consistent with our belief that an all-powerful, all-knowing creator God exists. As He reveals Himself to us, it stands to reason that understanding some aspects of Him might be beyond our human experience and understanding. So if you feel you can’t fully understand it, don’t worry about it. The important things are to know that there is one God, that there are three Persons in God, that God loves you and Jesus died for your salvation, and that the Holy Spirit is with you as a helper and counselor.

When speaking of the Trinity, theologian A. W. Tozer stated, “The doctrine of the Trinity … is truth for the heart. The fact that it cannot be satisfactorily explained, instead of being against it, is in its favor. Such a truth had to be revealed; no one could imagine it.”[45]

The apostles and disciples—who were all Jewish and who had all their lives believed there was only one God, and for whom believing otherwise was blasphemy—came to understand, especially after His resurrection, that Jesus, this man they knew and lived with, was God. They knew He wasn’t God the Father, but that He was God. Once Jesus had ascended into heaven and the promised Holy Spirit powerfully came into their lives at Pentecost, these same men came to understand the Holy Spirit as God, yet they knew that the Spirit was neither the Father nor the Son.

The writers of the New Testament understood, accepted, and wrote in terms of one God, and of the distinct persons of the Godhead. The early church believed it, and Christians today believe it. It’s at the heart of our faith.

The next part of this series will cover other aspects of the Trinity.


Unless otherwise indicated, all scriptures are from the Holy Bible, English Standard Version, copyright © 2001 by Crossway Bibles, a division of Good News Publishers. Used by permission. All rights reserved. Other versions frequently cited are The New International Version (NIV), the New American Standard Bible (NASB), The New King James Version (NKJV), and the King James Version (KJV).


Barth, Karl. The Doctrine of the Word of God, Vol.1 Part 2. Peabody: Hendrickson Publishers, 2010.

Berkhof, Louis. Systematic Theology. Grand Rapids: Wm. B. Eerdmans Publishing Company, 1996.

Cary, Phillip. The History of Christian Theology, Lecture Series. Lectures 11, 12. Chantilly: The Teaching Company, 2008.

Cottrell, Jack. What the Bible Says about God the Redeemer. Eugene: Wipf and Stock Publishers, 2000.

Craig, William Lane. The Doctrine of Christ, Defenders Series Lecture.

Garrett Jr., James Leo. Systematic Theology, Biblical, Historical, and Evangelical, Vol. 1. N. Richland Hills: BIBAL Press, 2000.

Grudem, Wayne. Systematic Theology, An Introduction to Biblical Doctrine. Grand Rapids: InterVarsity Press, 2000.

Kreeft, Peter, and Ronald K. Tacelli. Handbook of Christian Apologetics. Downers Grove: InterVarsity Press, 1994.

Lewis, Gordon R., and Bruce A. Demarest. Integrative Theology. Grand Rapids: Zondervan, 1996.

Milne, Bruce. Know the Truth, A Handbook of Christian Belief. Downers Grove: InterVarsity Press, 2009.

Mueller, John Theodore. Christian Dogmatics, A Handbook of Doctrinal Theology for Pastors, Teachers, and Laymen. St. Louis: Concordia Publishing House, 1934.

Ott, Ludwig. Fundamentals of Catholic Dogma. Rockford: Tan Books and Publishers, Inc., 1960.

Stott, John. Basic Christianity. Downers Grove: InterVarsity Press, 1971.

Williams, J. Rodman. Renewal Theology, Systematic Theology from a Charismatic Perspective. Grand Rapids: Zondervan, 1996.

[1] Kenneth Samples, What the Trinity Is and Isn’t—Part 1, 2007.

[2] Mark 1:11.

[3] John 5:20.

[4] John 15:26.

[5] William Lane Craig, The Doctrine of the Trinity 1, Defenders Series Lecture.

[6] Genesis 1:26.

[7] Genesis 3:22.

[8] Genesis 11:7.

[9] Isaiah 6:8.

[10] Proverbs 30:4.

[11] Psalm 2:12 NASB.

[12] Isaiah 48:16.

[13] Isaiah 61:1.

[14] Deuteronomy 6:4 KJV.

[15] Psalm 89:26.

[16] Isaiah 63:16 KJV.

[17] Matthew 6:9 KJV.

[18] Ephesians 4:6 KJV.

[19] 2 Peter 1:17 KJV.

[20] John 1:1–3.

[21] John 8:58 KJV.

[22] Colossians 1:15–20 NIV.

[23] Colossians 2:9 NIV.

[24] Hebrews 1:1–3 NIV.

[25] John 1:18 NASB.

[26] Acts 5:3–4 NIV.

[27] Psalm 139:7–10.

[28] 1 Corinthians 2:10–11.

[29] Genesis 1:2 NIV.

[30] 1 Corinthians 6:11 NIV.

[31] John 14:26 NIV.

[32] 2 Corinthians 13:14.

[33] Matthew 28:19.

[34] John 14:16–17.

[35] Matthew 11:27.

[36] Matthew 3:16–17.

[37] John 7:39.

[38] Mark 12:28–29.

[39] 1 Kings 8:60.

[40] Isaiah 45:5.

[41] Isaiah 45:21–22.

[42] Romans 3:29–30.

[43] 1 Corinthians 8:4.

[44] James 2:19.

[45] Tozer, A. W., The Knowledge of the Holy, NY: HarperCollins, 1961. p.18.