Our Triune God: One in Substance and Three in Person

From Issue: R&R – Issue 44 #4

[EDITOR’S NOTE: The following article was written by A.P. auxiliary writer Dr. Donnie DeBord (Th.M. and Ph.D. in Systematic Theology from Midwestern Baptist Theological Seminary). Dr. DeBord is an assistant professor of Systematic Theology and Bible at Freed-Hardeman University and teaches undergraduate and graduate courses on the Trinity.]

The doctrine of the Trinity remains misunderstood and neglected. Perhaps Christians see Trinitarian theology as impractical, too academic, or perhaps even unnecessary.1 Fred Sanders described the situation this way: “We tend to acknowledge the doctrine with a polite hospitality but not welcome it with any special warmth.”2 How can we believe or preach God’s good news until we know a bit about Who God is? In contrast with our contemporary neglect of the Triune God, Paul could not help but praise God as he reflected on how the Father has blessed us through Christ and sealed us with the Spirit, all of which is for the ultimate glory of God (Ephesians 1:3-14).3

Similarly, Peter said the Christian’s life is bound up in the foreknowledge of the Father, sanctification by the Spirit, and obedience to Christ—all due to the sprinkling of Christ’s blood (1 Peter 1:1-2). What some may see as “a dull or peculiar irrelevance turns out to be the source of all that is good in Christianity. Neither a problem nor a technicality, the triune being of God is the vital oxygen of Christian life and joy.”4 Just as the cherubim praise the thrice holy God, we too can become better worshipers as we look closer into the nature of God. The best doxologies, Giles Emory said, “do not regard an action of God…but rather they are focused directly on the glory of God and his sanctity. They do not express a wish, but rather they declare the reality of God.”5 I think Augustine was right when he said, “This is the fullness of our joy…to enjoy God the Trinity in whose image we have been made.”6

When working on my dissertation, I was advised to write an “elevator speech” explanation of what I was working on.7 So, how would we do this with the Trinity? It’s hard, but here is how I try to do it: our God exists as three persons who share the same substance.8

God Is One

Before we can appreciate the threeness of God, we must articulate the oneness of God. There is one God. Moses said, “Hear O Israel: The LORD our God, the LORD is one” (Deuteronomy 6:4). God alone is God (Psalm 86:10). Besides Him, there is no God (Isaiah 44:6). Zechariah 14:9 confirms: “And the Lord will be King over all the earth; on that day the Lord will be the only one, and His name the only one.” Paul said, “there is no God but one” (1 Corinthians 8:4). God is one, and we are to be singularly devoted to Him. God said, “You shall have no other gods before me” (Exodus 20:3). The New Testament, even while affirming the deity of Christ and the Spirit, commands Christians to believe in one God (James 2:19; 1 Corinthians 8:6).9

While there are three divine persons, each shares in the singular divine substance. They do not each have their own divine substance apart from the other two. That would result in three divine beings—three gods. It is best to see that the Son and Spirit eternally share in the Father’s divine nature. This sharing is without beginning and any diminishment (John 1:1; 5:26; 10:38; 15:26). This precision helps us honor the oneness of God while also maintaining the threeness of God. Matthew Barrett summarized this truth this way: “There is in him no composition, nor can he be compounded by parts. If he could, then he would be a divided being (parts are divisible by definition), a mutable being (parts are prone to change), a temporal being(parts require a composer), and a dependent being (depending on these parts as if they precede him).”10 God’s nature is one in every way. God’s “oneness” is the most extreme unity.

Each Divine Person Is “the LORD”

“The LORD” has been used in Scripture to translate the divine name with which God revealed Himself to Moses. God said He is the “I AM” (Exodus 3:14). God subsequently revealed His glory to Moses by passing by him and proclaiming His name “I AM” or “the LORD” (Exodus 33:19). God’s name “I AM” or “the LORD” has been understood to communicate God’s aseity (that God exists independent of any cause), uniqueness (holiness), transcendence, and faithfulness. The Bible helps us see that the Father, Son, and Spirit share the same essence by describing each of them as “the LORD.” The New Testament uses the word “Lord” to refer to the Father (Luke 1:32), the Son (Luke 2:11), and the Spirit (2 Corinthians 3:17-18). This is appropriate because the three share that same divine nature. In the ancient world, to name something was to describe its substance. The Father, Son, and Spirit share in one name (Matthew 28:19).

It would not be appropriate to describe the Father, Son, and Spirit as the great “WE ARE.” “They” are “the I AM” because the three share the same substance. There is only one substance and one divine consciousness shared by three persons. It would be difficult to avoid the charge of polytheism if we believed there were three divine beings with their own divine substances, or three “centers of consciousness,” or a society of divine beings. Instead, God has revealed His nature in the name “I AM.”

There is a novel trinitarian theology labeled social trinitarianism, which teaches that God is three distinct individuals (three beings) rather than the historic position of God as one Being (i.e., substance) shared by three persons. Briefly, social trinitarianism is the idea that each member of the Trinity is fully divine and that the divine persons enjoy a loving relationship with one another as distinct beings.11 Social trinitarianism is defined this way: “Each of the divine persons must have something—be it his own distinct substance, his own distinct intellect, his own distinct act and faculty of will, or so on—which is his alone, and which the others do not have in the same way.”12 So, instead of one substance shared by three persons, social trinitarians believe there are three beings who share a set of attributes that make them regarded as gods. There are, it seems, three divine substances. This model sees the Trinity as a family, society, or team. This position is put forward in contrast to the historic model of the Trinity that begins with the oneness of God and proceeds to investigate how the three divine persons share the singular divine substance.

In this social-trinitarian model, the divine persons do not share a singular substance; they each have their own divine substance. This may seem like a small differentiation, but the implications are quite troubling. In this paradigm, it is difficult to explain how there are not three gods. Similarly, in this view, the divine persons are closer to three humans who share in human nature but interact and may have different and/or submissive wills to other members of the divine family.13

Social trinitarianism, I believe, should be rejected because the Bible repeatedly affirms the oneness of God rather than three beings who happen to share common attributes belonging to a genus we call god. Furthermore, it seems dangerous to affirm a distinct will and being to each of the divine persons. This would appear to encroach upon the oneness of God.14 Furthermore, the social trinitarian model is a conspicuous leap from historic trinitarian theology.

So, the Father, Son, and Spirit exist and act with one undivided and inseparable substance. Since the entire Trinity shares the same substance, we know that honor, authority, power, eternity, and mind is shared by each of the three persons. The Father, Son, and Spirit have no distinction in nature, attitude, or will (John 1:1).

God Is Three

Why isn’t there just one divine person? Why is there a Trinity? The oneness of God is taught clearly in Scripture and is, perhaps, easier to understand than the threeness of God, but the threeness of God is revealed as well. These are difficult concepts to reconcile. Apart from Scripture, we would have little reason to believe in the threeness or triunity of God. But, as Fred Sanders said, “God made it known that his unity was a triunity precisely when the Father sent the Son and the Holy Spirit in the fulfillment of the promise of redemption.”15 This Divine Triunity is taught in several ways, but it is beautifully displayed as the Father, Son, and Spirit are routinely placed together as the God who saves. As Michael Horton said, “The confession ‘one God in three persons’ arises naturally out of the triadic formulas in the New Testament in the context of baptism (Mt 28:19 and par.) and liturgical blessings and benedictions (Mt 28:19; Jn 1:18; 5:23; Ro 5:5-8; 1 Co 6:11; 8:6; 12:4-6; 2 Co 13:13-14; Eph 4:4-6; 2 Th 2:13; 1 Ti 2:5, 1 Pe 1:2).”16

God is eternally one but never lonely or isolated. “God is love” (1 John 4:8,16). This divine love is eternally and perfectly shared between the Father, Son, and Spirit. We see glimpses of this in Scripture as Jesus is described as the Father’s Son and the beloved Son. The Spirit is also described as “the Spirit of God” and “the Spirit of Christ.” Jesus’ pronouncement of the baptismal formula links the three persons to one name. Individuals are baptized “in the name of the Father and of the Son and of the Holy Spirit” (Matthew 28:19). Paul’s doxology groups the three together, saying, “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 13:13). So, the three persons of God are linked together in worship and works of salvation.

The oneness and threeness of God are not math problems to be reconciled or contradictions requiring magical theological maneuvers to maintain the unity of Scripture. The oneness and threeness of God describe two categorically distinct truths: (1) there is one divine substance, and (2) three persons eternally share one divine substance. The oneness and threeness of God are mysteries revealed to us. We should accept them, marvel at them, and investigate these truths as best we can. God’s threeness is revealed to us in Scripture in several different ways. In each of these ways, we can see the one divine essence is shared by the three divine persons.

The One God Who Creates

Scripture opens with the truth that “God created the heavens and the earth” (Genesis 1:1). Even in the Old Testament, we see this creative act involved more than one divine person. Proverbs 8:22-36, for example, was understood by ancient Jews and Christians to refer to a second divine person present at creation. While we may immediately think of God the Father in Genesis 1:1, John taught us the Son was “in the beginning with God” and that “all things were made through him, and without him was not anything made that was made” (John 1:2-3). Furthermore, it is in Christ that “all things hold together” (Colossians 1:17).

Moving forward in the Creation account, we find the Holy Spirit was active in creation as well. The Son was not alone in the work of creation. During the creation of the heavens and earth, “the Spirit of God was hovering over the face of the waters” (Genesis 1:2). The phrase “Spirit of God” is found around 24 more times in the Bible, and each time this refers to the Holy Spirit. The words describing the Spirit’s creative work in Genesis 1:2 are echoed in Luke 1:35 to describe the Spirit’s work in the creation of Christ’s human nature. Subsequently, Christians are said to have been born again by “water and the Spirit” (John 3:5; Titus 3:5-6). So, it is right to say God created the heavens and the Earth. We can see this was not an isolated work. Rather, it was the collective work of the Triune God.

God the Son

The Bible also describes the Son’s relationship to the Father in such a way that affirms His deity as well as His distinct personhood. The Son is distinct from the Father but also eternally shares in the divine substance (John 1:1). Jesus calls God His own Father, but Jesus called God His Father differently than we can claim that God is our Father. When Jesus called God Father, He was claiming to be equal with the Father (John 5:18,26). The Son eternally receives His divine life from the Father (John 5:26). The Son is able to bring many sons to glory because He Himself is Son (Galatians 4:4-6).17 As the divine Son, He is installed as King by the Father and should be worshiped (Psalm 2:2,12; see Acts 4:25-26; Hebrews 1:5; Psalm 45:6-7; Hebrews 1:8-9).

The Gospel of John identified Christ as God by identifying Him with the I AM. The seven main I AM statements (John 6:35; 8:12; 10:9,11; 11:25; 14:6; 15:1) and other important I AM constructions (John 4:26; 6:20; 8:18,24,28,58; 13:19; 18:5,8) point to Jesus being the I AM. John’s presentation of Jesus as the “I AM” points his readers back to Exodus 3:14-15 and 33:17-20, where God reveals His nature in the proclamation of His name “Yahweh,” the great “I AM.”18

Since there is one divine substance, the Son was able to say, “Believe Me that I am in the Father and the Father is in Me” (John 14:11). This sharing of the singular divine essence is implied again as Jesus said, “The words that I say to you I do not speak on My own, but the Father, as He remains in Me, does His works” (14:10). The one divine essence is shared by Father, Son, and Spirit in such a way that Jesus can say “I am in the Father and the Father is in Me.” Since He shares the same nature, Jesus was able to say “whoever has seen me has seen the Father” (14:9).

There is an eternal sharing or communication of the divine nature. John described it this way: “we have seen his glory, glory as the only Son from the Father, full of grace and truth” (John 1:14). Colossians 1:15 describes Christ as “the image of the invisible God.” Hebrews 1:3 describes the Son as “the radiance of the glory of God and the exact imprint of his nature.” In this we can imagine the origin of glory and the glory radiating around the original glory. Christ’s Sonship seems to be a shorthand way of teaching that Jesus shares in the Father’s divine nature.19

Furthermore, Christ demonstrated His divinity (His sharing in the divine nature) as He performed divine works. Christ can forgive sins because He shares in the divine substance (Mark 2:1-12; Matthew 9:5-6). The Word both is God and is with God (John 1:1). In Isaiah 45:23, we learn that every knee should bow, and every tongue confess the LORD. Jesus is able to “explain” the Father because He is “God the only Son, who is in the arms of the Father” (John 1:18, NASB 2020).

Jesus said He would “give life” as a divine work (John 5:21,25). Jesus explained that He is able to give life because the Father has eternally shared His divine life with Him (John 5:26). The Son, because He shares in the singular divine substance, should be honored as the Father is honored (John 5:23). In Philippians 2:10-11, we see that every knee shall bow to Christ who, as Lord, shares in the divine substance. Finally, “perhaps no stronger assertion of Christ’s deity could be made than the announcement given by all of the apostles that there is no other name in heaven or on earth by which we may be saved (John 1:12; Acts 3:16; 4:12; 5:41; Romans 10:13; Philippians 2:9; 1 Peter 4:14; Revelation 2:13). This could mean only that Jesus of Nazareth was none other than Israel’s Great King, Yahweh, whose name alone was to be invoked.”20

God the Spirit

This Spirit is described as “God” (Acts 5:4) and the “Spirit of the Lord” (Acts 5:9). The Spirit was described as God when God’s people sinned against Him (Isaiah 63:10; Matthew 12:31-32; Acts 5:3). The Spirit is grouped with the Father and Son as the three share the one “name” or substance of Matthew 28:19. The Spirit is also included with the Father and Son in texts like 2 Corinthians 13:14 in which Paul prayed, “The grace of the Lord Jesus Christ and the love of God and the fellowship of the Spirit be with you all.” The Spirit was present with the Father in Matthew 3:16 to confirm Jesus’ Sonship when He was baptized in the Jordan River.

The deity of the Spirit is demonstrated in the Spirit’s involvement in work only God can do. This exclusively divine activity is seen in the Spirit’s eternal pre-existence and work to bring about creation (Genesis 1:2) and the regeneration of God’s people (John 3:3-5; Titus 3:5-7). The Spirit is omnipresent (Psalm 139:7-10). The Spirit is omniscient (Isaiah 40:13-14). The Spirit reveals the future (1 Timothy 4:1). The Spirit was described by the Son as “another Helper” and “the Spirit of Truth” to be with the Apostles instead of the incarnate Christ (John 14:16-18). God’s love is “poured into our hearts” through the Spirit (Romans 5:5). The Spirit, as a divine work, sanctifies God’s people (1 Peter 1:2). Christians are the “temple of God” because God’s Spirit dwells within them (1 Corinthians 3:16; 6:19).

The deity of the Spirit is also seen in the works of the Spirit during the incarnation of Christ. This divine work was prophesied in Isaiah 42:1-14 as God revealed that His Spirit would rest upon His chosen Servant. The Spirit, as a divine person, created the human nature of Christ in Mary’s womb (Luke 1:35; Matthew 1:18). Jesus’ miraculous work was completed through the Spirit’s direction and empowerment (John 3:34; Matthew 12:28). Finally, the Spirit is also said to have raised Christ’s body from the dead (Romans 8:11).21


The oneness and threeness of God demonstrate God’s perfection. Instead of isolation or loneliness, our triune God eternally enjoys His divine fullness. The three persons of God also remind us of our own Christian certainty. The Father, Son, and Spirit share their overflowing love with us and exalt us for their own glory. The triune God is our great comfort in every situation in life. We can know the Father, Son, and Spirit are at work to bring us home.

So, how do we speak of God appropriately? Speak of God as He has revealed Himself. This self-revelation of God from God is accommodative—it is as much as we can handle, but it is also accurate. We can know God as the one God who exists as God the Father, the Son of God, and the Spirit of God. The Father, Son, and Spirit are the three persons who share the same divine substance.

Our affections and worship should be singularly focused on God. And, as we focus on the oneness of God, we are also compelled to consider the three persons of God. We can agree with Gregory of Nazianzus, who said, “No sooner do I conceive of the one than I am illumined by the splendor of the three; no sooner do I distinguish them than I am carried back to the one.”22 Indeed, there is one divine essence. We have our hope in the one God, Who, through actions appropriate to the three persons, saved us and brought us to Himself for our salvation and His glory.


1 And sadly, some consider the concept self-contradictory, rejecting altogether the reality of the triune God.

2 Fred Sanders (2017), The Deep Things of God: How the Trinity Changes Everything (Wheaton, IL: Crossway), second edition, p. 13.

3 All Scripture references are from the ESV unless otherwise noted.

4 Michael Reeves (2012), Delighting in the Trinity: An Introduction to the Christian Faith (Downers Grove: IVP Academic), p. 18.

5 Gilles Emery (2011), The Trinity: An Introduction to Catholic Doctrine on the Triune God, Thomistic Ressourcement Book 1 (The Catholic University of America Press), p. 6.

6 Augustine, On the Trinity, 1.8.18.

7 An elevator speech is a brief explanation of what you are studying.

8 John Frame explained “substance” this way: “Substance means something like ‘what he really is.’ So, the Father really is God, the Son really is God, and the Spirit really is God. Or you can think of the one substance as the ‘Godness of God.’ All three persons have that Godness” [John Frame (2006), Salvation Belongs to the Lord: An Introduction to Systematic Theology (Philipsburg, NJ: P&R), p. 35].

9 John Owen said, “Hence it follows, that when the Scripture revealeth the Father, Son, and Holy Ghost to be one God, seeing it necessarily and unavoidably follows thereon that they are one in essence (wherein alone it is possible they can be one), and three in their distinct subsistences (wherein alone it is possible they can be three),—this is no less of divine revelation than the first principle from whence these things follow” [The Works of John Owen (n.d.), ed. William H. Goold (Edinburgh: T&T Clark), p. 379)].

10 Matthew Barrett (2021), Simply Trinity (Grand Rapids, MI: Baker), p. 137.

11 This theology begins with a combination of several post-Enlightenment ideas. First, the idea has roots in Hegelian philosophy, as it sees the basic distinction in ultimate reality as the Father/Son distinction rather than the Creator/creature distinction. Then there is the acceptation of the Schleiermachian idea that the Old Testament writings had to be against the polytheistic pagan deities, but now that the pagan deities are no longer heavily worshiped the plurality of God can be freely expounded. Finally, the influence of modernity’s emphasis on personality and relationship combines with Hegel and Schleiermacher to provide a brand-new way of looking at the Trinity. This model has three persons who choose to love each other and work together, but they are three different “people” just as you and I are different people. This novel view is popular, but it does not present God as one.

12 Michael Joseph Higgins (2023), “Simply Given: Self-Gift and Consubstantiality in Aquinas and Social Trinitarianism,” International Journal of Systematic Theology, p. 3.

13 This description is, admittedly, brief and overgeneralizing. For a better introductory description of the position, see “The Perfect Family: Our Model for Life Together Is Found in the Father, Son, and Holy Spirit” (1988) by Cornelius Plantinga in Christianity Today, March 4.

14 For more thorough responses to social trinitarianism, see chapters 8 and 9 of Stephen Holmes (2012) The Quest for the Trinity: The Doctrine of God in Scripture, History, and Modernity (Downers: IVP Academic) andMatthew Barrett (2021), Simply Trinity (Grand Rapids, MI: Baker).

15 Fred Sanders (2016), The Triune God in New Studies in Dogmatics, ed. Michael Allen and Scott Swain (Grand Rapids, MI: Zondervan), p. 37.

16 Michael Horton (2011), The Christian Faith: A Systematic Theology for Pilgrims on the Way (Grand Rapids, MI: Zondervan), p. 274.

17 “Son” or “Son of God” can refer to Adam, Israel, or the installation of a king by his father. The Bible also uses the word Son to refer specifically to the relationship between Father and Son. This shared relationship is built on their shared nature. “Son” or “sonship” can focus on a declaration of kingship or enthronement. While there are passages in which this ancient Near Eastern meaning is applied to the Son, it is also true that Sonship is a way in which Jesus affirmed His eternal equality with the Father. This is clear in John 5:17-18 and Hebrews 1. For a healthy discussion of Jesus as Son, see Herman Bavinck, Reformed Dogmatics, 2:274-275 and R.B. Jamieson (2021), The Paradox of Sonship: Christology in the Epistle to the Hebrews in Studies in Christian Doctrine and Scripture (Downers Grove, IL: IVP Academic; An Imprint of InterVarsity Press).

18 Keown said, “John does not use the construct neutrally or merely as an identification device. Most likely, they point to Jesus’ divinity in terms of Exodus 3:14 (LXX): ‘I am the one who is’ (egō eimi ho ōn). It also calls to mind Isaiah 40-55 where ‘I am’ is used as a title for God (Isa 43:10,25; 45:18; 46:4; 51:12; 52:6). This is confirmed by the Jews’ response; they recognized it as a radical claim to divinity and sought to kill him (John 5:18; 8:59; 10:33)’” [Mark J. Keown (2018), Discovering the New Testament: An Introduction to Its Background, Theology, and Themes: The Gospels & Acts (Bellingham, WA: Lexham Press), 1:291].

19 This sharing in one divine substance is especially clear in 1 Corinthians 8:6 as Paul said, “Yet for us there is one God, the Father, from whom are all things and for whom we exist, and one Lord, Jesus Christ, through whom are all things and through whom we exist.” Bible readers are accustomed to reading “Lord” as a reference to God in the Old Testament. In the New Testament, the word “Lord” refers overwhelmingly to the Son rather than the Father.

20 Michael Horton (2011), The Christian Faith: A Systematic Theology for Pilgrims on the Way (Grand Rapids, MI: Zondervan), pp. 276-277.

21 Interestingly, the resurrection is also attributed to God’s work (Romans 6:4; Acts 2:32). Jesus said He laid down His own life so that He could “take it up again” (John 10:18, cf. John 2:18). Galatians 1:1 attributes the resurrection of Christ to the Father. So, who raised Jesus? The resurrection of Christ leads us to accept what is called “the doctrine of inseparable operations.” This just means that since the three divine persons share one divine nature, each person of God is involved in the works which are only appropriate for the individual persons. Only the Son of God could make us to be the sons and daughters of God. This work is especially appropriate for Him as Son. The Spirit is involved in this work, and the Father is involved in this work, but the Christian’s adoption to sonship is through the Son Who worked by the Spirit at the Father’s direction. The three persons of God share one divine essence, but there are three persons who operate as is fitting for each of them based on their eternal divine relations. This helps us understand a bit better how “through Him we both have access in one Spirit to the Father” (Ephesians 2:18).

22 Gregory Nazianzen, Orations, 40.41.


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