There is no way to “make the Trinity ‘easy,'” but the Church is always in need of clear and accessible instruction on this all-important doctrine. This article is a simple-English introduction to the Church’s historic teaching on the Triune God. It is followed by a list of recommended resources for further study.
Who is God?
Imagine meeting someone for the first time, and they ask, “Who are you?” Would you say, “I am strong, wise, and good”? Or, “I am a human being—I have a body and soul”? Of course not! These answers tell us what you are (a strong, good, wise human being), but they do not tell us who you are. When someone asks, “Who are you?” we give our personal name—for example, “I am John” or “I am Mary.”
Now, consider the question, “Who is God?” Many people would say, “God is almighty, perfectly good, and perfectly wise.” Or, “God is a divine being—he is pure spirit.” These things are all true and very important. However, these answers tell us what God is (an almighty, good, and wise spirit). A better way to answer the question, “Who is God?” is to give “the name of the Father and of the Son and of the Holy Spirit” (Matthew 28:19). There is something three about who God is. The word “Trinity” (from the Latin trinitas) means “three.” The Trinity is the answer to the question “Who is God?”
It is good to say, “I believe in God,” or to pray, “God, help me.” But even a Jew or Muslim can speak and pray this way. Only a Christian can say, “I believe in the Father, and in the Son, and in the Holy Spirit.” Only a Christian can pray, “Father, provide for me. Jesus, forgive me. Holy Spirit, guide me.” Only a Christian knows who God truly is. This is why Gregory the Theologian wrote, “When I say ‘God,’ I mean ‘Father, Son and Holy Spirit’” (Oration 38).
Pray Before You Continue
If the Trinity is the answer to the question “Who is God?” then it should help us to have a deeper personal relationship with God. The goal of our study is to know and glorify the Triune God. Before you continue reading this article, pause to say this beautiful Trinitarian prayer of John Stott. If you are reading this article in the afternoon or the evening, you can say “Good afternoon, Heavenly Father” or “Good evening, Heavenly Father.”
Good morning, Heavenly Father.
Good morning, Lord Jesus.
Good morning, Holy Spirit.
Heavenly Father, I worship you as the creator and sustainer of the universe.
Lord Jesus, I worship you as the Savior and Lord of the world.
Holy Spirit, I worship you as the sanctifier of the people of God.
Glory to the Father, and to the Son, and to the Holy Spirit.
Heavenly Father, I pray that this day I may live in your presence and please you more and more.
Lord Jesus, I pray that this day I may take up my cross and follow you.
Holy Spirit, I pray that this day you will fill me with yourself and cause your fruit to ripen in my life: love, joy, peace, patience, kindness, goodness, faithfulness, gentleness and self-control.
Holy, blessed and glorious Trinity, three persons in one God, have mercy upon me. Amen.
One and Only One God
In the Old Testament, God taught his people to confess that there is only one God. “Hear, O Israel: The LORD [Yahweh] our God, the LORD [Yahweh] is one” (Deuteronomy 6:4). This belief set Israel apart from other nations that believed in many gods. Jesus and the apostles continued to teach that there is one God (Mark 12:29; 1 Timothy 2:5). There are not three gods or ten gods. There is only one invisible, almighty spirit that we call “God.”
At the same time, there are hints in the Old Testaments that there is something three or plural in the one God. When God makes Adam and Eve, he says, “Let us make man in our image, after our likeness” (Genesis 1:26). To whom is God speaking? Why does he say “our” image (plural)? When Isaiah has his vision of God in the temple, he hears the angels crying “Holy, Holy, Holy” (Isaiah 6:3), and the Lord says, “Who will go for us?” (Isaiah 6:8). In Psalm 110:1, Yahweh speaks to another who is identified as David’s Lord. How can the Lord speak to the Lord?
The best answer to these questions is provided in the New Testament. The Bible is one great story that waits to reveal some truths until the end, when we are better prepared to receive them. God revealed the deepest truth about who God is when he sent his Son to become incarnate and sent the Holy Spirit at Pentecost. The gospel reveals that there truly is something three about the one God. The Trinity is the greatest revelation made to humanity. It is the heart of the Christian faith.
The Incarnation: The Son of God Revealed
God revealed more about himself when, in the fullness of time, “God sent forth his Son” (Galatians 4:4; cf. Hebrews 1:2; Matthew 16:16). “For God so loved the world, that he gave his only Son” (John 3:16). If God sent his Son, then the one God must be a Father who has a Son. If the Son was sent into the world, then he was God’s Son before he was sent.
Jesus claimed to be the Son of God in a unique way that made him equal with God the Father. In John 5:18, the Jews tried to kill Jesus because “he was even calling God his own Father, making himself equal with God.” When Jesus said, “Before Abraham was, I am” (John 8:58), he was claiming to be Yahweh (Exodus 3:14). In 1 Corinthians 8:6, Paul affirms Deuteronomy 6:4 (“the Lord is one”), but includes the Lord Jesus Christ within the identity of the one Creator God of Israel.
As the Son of God the Father, Jesus is not the Father. A son is not the same person as his father. In John 1, Jesus is called “God” (1:1) and “the only God” (1:18), yet he is said to be “with God (the Father)” (1:1) and to be “the only Son from the Father” (1:14). The Son was sent by the Father (John 3:16), prayed to the Father (Matthew 26:39), and asked the Father to glorify him so that he could glorify the Father (John 17:1). If the Son is the Father, then the Son sent himself, talked to himself, and asked himself to glorify himself so that he could glorify himself. That does not make any sense!
There is a real distinction between the Father and the Son, but they are perfectly united as one God. In John 14:11, Jesus taught, “I am in the Father and the Father is in me.” The Father and the Son dwell completely in one another because they are one eternal, invisible spirit. They are not two separate spirits or two separate gods. The doctrine of the Trinity is the result of serious reflection on these teachings of Jesus, as well as his teaching about the Holy Spirit.
Pentecost: The Holy Spirit Revealed
Jesus constantly spoke about his Father, but he also spoke about another: the Holy Spirit. Jesus promised to ask the Father to send the Spirit (14:16–17), and to send the Spirit who proceeds from the Father (John 15:26). Jesus assured the disciples that the Father would send the Spirit in his name (Acts 14:26). After his resurrection and ascension, Jesus received from the Father the promise of the Holy Spirit, and poured out the Spirit on his disciples at Pentecost (Acts 2:33).
As the Spirit of God, the Holy Spirit is equal with the Father and the Son. When Ananias lied in Acts 5, Peter asked him, “Why has Satan filled your heart to lie to the Holy Spirit? … You have not lied to man but to God” (Acts 5:3–4). The Holy Spirit is God. He is eternal (Hebrews 9:14) and all-knowing (1 Corinthians 2:10–11).
At the same time, the Holy Spirit is not the Father or the Son. The Holy Spirit is another, just as the Son is another (not the Father). The Spirit is sent by the Father and the Son, speaks only what he hears from the Father and the Son (John 16:13), and comes to glorify the Son (John 16:14). If the Spirit is the Father and the Son, then the Spirit sent himself, speaks what he hears from himself, and seeks to glorify himself. That does not make any sense!
Key New Testament Passages
Matthew 3:13–17 is one key passage in which the Father, the Son, and the Holy Spirit are seen interacting. Jesus is baptized, the Father speaks from heaven (“This is my beloved Son, with whom I am well pleased”), and the Holy Spirit reveals his invisible presence by appearing like a dove and coming to rest on Jesus. It does not make sense to say that the Father is the Son or that the Holy Spirit is the Son. If that was the case, then the Son would be throwing his voice up into heaven to say how pleased he is with himself, while descending upon himself to rest upon himself! There are three at the baptism of Jesus.
The heart of Christian teaching on the Trinity is the baptismal formula in Matthew 28:19: “make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit.” In the Old Testament, God put his name “Yahweh” upon his people, and called them to bear his name to the nations (Numbers 6:27; Deuteronomy 28:10). In the New Testament, God puts the name of the Father, and of the Son, and of the Holy Spirit upon his people, and sends them into the world on mission. This indicates that the Father, the Son, and the Spirit are each God, and yet distinct from one another. The doctrine of the Trinity helps Christians to understand what it means to be baptized in the name of the Trinity. In fact, all Christian theology works out from this central point.
Words Matter: Key Terms in Church History
The gospel reveals that there is something three about the one God. However, God is not three and one in the same sense. There are not three gods and one god. That would be a contradiction (and a rejection of clear biblical teaching!). We need words to explain the sense in which God is three, and the sense in which “the Lord is one” (Deuteronomy 6:4).
Most in the early church spoke Greek or Latin, and they spent centuries discussing which words to use. It should not surprise us that it is sometimes difficult to find language to use to speak about God. Human language cannot perfectly describe God. Yet, nothing is more important than what we believe about God, so we must choose our words very carefully so that we do not confuse or mislead others.
The words ousia (Greek) and substantia (Latin) were recognized as the best words to point to what is one about God—what is common to the Father, the Son, and the Holy Spirit. The Lord is one ousia or substantia. These words point to what something is (recall the illustration from the beginning of this lesson). God is one invisible spirit, eternal, perfect in power, wisdom, and goodness. In English, the word substance (from the Latin substantia) is used for what is one about God. The words nature, being, or essence are also used. There is only one divine substance or being.
The words hypostasis (Greek) and persona (Latin) were used to point to what is three in God. The Father, the Son, and the Holy Spirit are three real and distinct hypostases or personae. These words point to who someone is. Again: The Trinity is the answer to the question “Who is God?” In English, the word persons (from the Latin personae) is used for what is three in God. We do not use the words “people” or “individuals,” since that implies separate beings or substances.
Even these terms have their weaknesses and limitations, and they must be carefully explained to avoid misunderstanding. In every language, theologians must think carefully about which words to use. Sometimes a language does not have good words to use. But finding widely recognized and understood words is very helpful. For example, these words help us to clearly explain what John 10:30 does and does not mean. When Jesus said, “I and the Father are one,” he meant, “I and the Father are one being or substance”; he did not mean, “I and the Father are the same person.” When John wrote, “The Word was with God, and the Word was God” (John 1:1), he meant, “The Son was with the person of God the Father, and the Son was of the same divine being or substance as the Father.”
Why We Struggle to Understand
While these distinctions are helpful, the Trinity is still difficult for us to understand. This is in part because our finite human minds can never fully understand the infinite God. But it is also because there are no other beings in all creation that are three persons of one single substance. We usually learn by comparing new things with what we already know. But we cannot look around in the world and find another single being that is three persons.
Consider a human being. In each human body and soul that exists, there is only one person—“John” or “Mary.” If a single human being claimed to be more than one person, it would not make sense, because we know that this is not how human beings exist. However, God is not human! God is a completely different kind of being from any other kind of being that we can observe. God has revealed to us that in the one divine being, there truly are three persons. We simply receive and believe by faith what God has revealed. Our mind cannot fully understand God, but we rejoice in what God has revealed, and wait to know and enjoy God better when we are in heaven.
How to Avoid False Teachings
Some people try to fit the Trinity into their own understanding, based on what they can observe in creation. Trinitarian Christians are careful not to divide the one substance of God, confuse the three persons in God, or treat any divine person as inferior or unequal in substance.
1. Do not divide the substance. The Father, Son, and Holy Spirit are not three parts that make up a whole. God is without parts. God is not like one egg with three parts (the shell, the yoke, and the white). God is not like one flower with three petals. These illustrations reflect a heresy called partialism.
2. Do not confuse the persons. Some people claim that the Son is just the Father wearing a different mask, or that the Spirit is just the Son showing up in a different form. However, we have already seen how the Father, the Son, and the Holy Spirit relate to one another as distinct persons. The Father is not the Son; the Son is not the Holy Spirit. God is not like a single water molecule which can exist in three modes (as a frozen solid, a liquid, or a gas). God is not like a man who puts on three different hats or masks. God is not like a man who has three roles (e.g., as a father, husband, and employee). These illustrations reflect a heresy called modalism which denies the distinct personhood of the Son and the Spirit. Modalism is also called Sabellianism (after a false teacher in the third century named Sabellius).
3. Do not treat any person as inferior or unequal in substance. Another destructive teaching is that the Son is inferior to the Father. Some people claim that the Son was the first and greatest being created by the Father. They may exalt Jesus and call him “divine,” but they do not teach that he is equal with the Father or that he has always existed. This heresy is called Arianism (after a false teacher in the fourth century named Arius). Arians teach that the Son is merely of a similar substance [homo-i-ousious] with the Father. However, the Bible teaches that the Son is “of one substance [homo-ousios] with the Father” (Nicene Creed). The Son and the Spirit are equal with the Father in power, glory, and eternity. They are worthy of worship and able to save us by their almighty power.
Why “Father,” “Son,” and “Spirit”?
To truly understand the doctrine of the Trinity, we need to take a closer look at the three persons. Why are the first and second persons called “the Father” and “the Son”? Why is the third person called “the Holy Spirit”? The names are not meaningless. The names tell us something true and eternal about God. Even before the creation of the world, God was the Father, the Son, and the Holy Spirit.
“The Father” and “the Son”
Although God is our Father in heaven (Matthew 6:9), the first person of the Trinity is not called “the Father” for this reason. The first person is called “the Father” because he is the eternal Father of a Son! Likewise, the second person is called “the Son” because he is the eternal Son of the Father. The very names “Father” and “Son” indicate this relation. The Father and the Son both have the eternal, uncreated life which belongs to God alone, but this life is “granted” to the Son by the Father (John 5:26).
Since the Father and the Son are both eternal, the Father does not “grant” life to the Son in a moment of time. The Father does not create the Son. The Father eternally “begets” or “brings forth” the Son in a way that is known only to God. This is a central teaching of the Nicene Creed: “We believe in … one Lord Jesus Christ, the only-begotten Son of God, begotten of the Father before all worlds; God of God, Light of Light, very God of very God; begotten, not made.”
This is a great mystery. We can barely understand human birth! How much less can we understand what it means for God the Father to eternally bring forth the Son? The church fathers often pointed to Hebrews 1:3, which says that the Son is “the radiance of the glory of God and the exact imprint of his nature.” A light always has its radiance (e.g., see (Athanasius, Discourse I Against the Arians 14.12). As long as a candle is burning, it radiates light. Since the Father is an eternal Light, he always radiates his Son. The Father never began to radiate the Son. He will never stop radiating the Son. The Father and the Son exist in an eternal relation of “radiating” and “being radiated.” Jesus is “God of God [the Father], Light of Light [the Father]” (Nicene Creed).
“The Spirit”
The name “Spirit” also points to something that is eternally true of the third person of the Trinity. The phrase “Spirit of God” is not like the phrase “spirit of Moses” or “soul of Abraham,” in which “spirit/soul” refers to the spiritual or immaterial part of a human being. God is pure spirit and does not have parts. Instead, the phrase “Spirit of God” indicates that the Spirit is from the Father, even as the Son is from the Father. The biblical word for “Spirit” can also be translated as “Breath.” As a person breathes his breath, the Spirit “proceeds” from the Father (John 15:26).
Many Christians believe that the Spirit also eternally proceeds from the Son. In the sixth century, the Western Church added the phrase “and the Son” (filioque in Latin) to the Nicene Creed: “the Holy Spirit … proceeds from the Father [and the Son].” Some common arguments in favor of the filioque are that “the Spirit of God” is also called “the Spirit of Christ” in Romans 8:9, and that the Son’s sending (John 15:26) and breathing (John 20:22) of the Spirit in time reflects an eternal relation to the Spirit, just as the Father’s sending of the Son reflects his eternal relation to the Son.
Since the Spirit is eternal, the Spirit is not brought forth in a moment of time. The Spirit is not created by the Father. The Father eternally “breathes” or “spirates” the Spirit. We do not know exactly what it means for the Spirit to eternally “proceed” from the Father, but we do know that it is not the same as being “begotten.” Otherwise, the Father would have a second Son!
The Key Points Summarized
The eternal begetting or generation of the Son and the eternal procession of the Spirit are difficult to understand. The key truths that need to be known by all Christians are summarized in the Athanasian Creed:
- The Father is not from anyone. He is not created or begotten. (He is unbegotten).
- The Son is from the Father alone. He is not made or created. He is (eternally) begotten.
- The Holy Spirit is from the Father [and from the Son]. He is not made, created, or begotten. He (eternally) proceeds.
- Therefore, there is one Father, not three Fathers. There is one Son, not three Sons. There is one Holy Spirit, not three Holy Spirits.
Power to Explain
This teaching explains why we ordinarily speak of the Father, Son, and Spirit (in that order), instead of the Spirit, Son, and Father (or some other order). The three persons are equal in power and authority because they are one God; however, the Father is the eternal source of the Son, and the Father [and the Son] are the eternal source of the Spirit. Therefore, it is fitting to refer to them in the order of Father, Son, and Spirit.
This teaching also explains why the Bible says “Son of God” and “Spirit of God” instead of “God the Son” or “God the Holy Spirit.” Since the Son and the Spirit are both God, we may refer to them in this way. However, it is fitting to refer to the Son and the Spirit in relation to the Father. The phrase “God the Son” emphasizes that Jesus is God; the phrase “Son of God” indicates that Jesus is “God of God” (Nicene Creed).
Finally, this teaching helps us to better understand the gospel. Any person of the Trinity could have become human to save us. However, it is fitting that the Son who is eternally begotten of the Father would be sent by the Father. It is fitting that the Son who is eternally begotten of the Father without a mother would be born of a mother in time without a father. It is fitting that the Spirit who eternally proceeds from the Father [and the Son] would be sent by the Father and the Son to give us life. The gospel reflects something eternally true about God!
Sharing in the Love of the Trinity
When we study the doctrine of the Trinity, we begin to better understand who God is, and this helps us to understand why God does what he does. In conclusion, consider three key points.
1. The Trinity explains what it means to say “God is love.” Imagine if a man lived alone in a cabin in the middle of a desert and never talked to anyone. Then, after 20 years, he came out of his cabin and said to you, “I am loving.” Would you believe him? Probably not! A loving person lives in relationship with others. They do not isolate themselves from everyone. The Bible says, “God is love” (1 John 4:8). If God is only one person, who was God loving before he created the world? But if God is three persons, then it makes sense to say that God is love. Jesus prayed to the Father and said, “You loved me before the world began!” (John 17:24). If you could go back in time before Genesis 1:1, there would only be one thing left: The Father loving the Son and the Spirit; the Son loving the Father and the Spirit; and the Spirit loving the Father and the Son. What a beautiful picture! In the very being of the one God is a communion of loving persons! God is love!
2. The Trinity explains why God created and redeemed the world. God did not create the world because he was lonely. God did not need someone to love. But it is the nature of love to share itself and to bring forth new life. God created the world out of pure love and goodness. He created human beings to share in his love. Adam and Eve walked with God in the cool of the day in the garden of Eden. Human beings were created to know, love, and enjoy the Father, the Son, and the Holy Spirit. We were created for the Trinity! When human beings chose to disobey God and fell into sin, God did not abandon us. The Father sent the Son and the Spirit to save us so that we could recover the purpose for which we were made. The purpose of salvation is to bring us home to the Trinity!
3. The Trinity explains the purpose of the church and the church’s final destiny. God created human beings in his image and likeness (Genesis 1:26), and said that it was not good for man to be alone (Genesis 2:18). We reflect the love of the Trinity when we live in loving relationship with one another. Some people take pride in being alone. They say, “I don’t need anyone else!” This is a sad result of the fall. Perhaps they have been hurt by other people and want to protect themselves. God did not intend for us to live this way. Because God is the Trinity, we must take the risk of living in a loving community with others. The Church is the place where God is reuniting humanity which has been divided from one another by sin. In John 17:22, Jesus prayed that the Church would become one even as he and the Father are one. Obviously the many members of the church do not become one human being. But when we live in unity and harmony, we reflect the perfect unity of the Trinity. In heaven, the Church will live in perfect fellowship with the Father, the Son, and the Holy Spirit. What a wonderful day that will be!
Conclude with Praise and Worship
As you conclude this article, take a moment to praise and worship the Triune God. Christian worship is Trinitarian from start to finish, because the Trinity is who we worship!
The Gloria Patri (“Glory to the Father”) is ancient prayer of praise to the Trinity that is still used by many Christians in daily prayer and in every church service:
Glory be to the Father, and to the Son, and to the Holy Spirit, as it was in the beginning, is now, and ever shall be, world without end. Amen.
The Trinitarian benediction in 2 Corinthians 13:14, which is also used by many Christians in daily prayer and in their church services, is a fitting conclusion:
The grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit, be with us all.
For further study, see “Books and Resources on the Trinity.”
