The Trinity

Why We Should Teach It

by Frank D. Macchia

I recently lectured to some students on the doctrine of the Trinity — the one God who is eternally three in person: Father, Son, and Holy Spirit. I was explaining the historic importance of the doctrine for the Christian life when a student raised her hand. She wasted no time getting to the point: “The term Trinity is not in the Bible,” she complained. She then proceeded to warn of the confusion that can occur when focusing on such a difficult doctrine in the church. “Shouldn’t we just concentrate on the simple gospel?” she asked.

“Though the technical term Trinity is not in the Bible,” I replied, “the basic concept behind it is there.” I went on to note that even the simplest expressions of the gospel imply the Trinity. John 3:16, for example, implies that the Father sent the only Son into the world so we might through the Spirit know life eternal (cf. John 1:18; 7:37–39). Awareness of the doctrine of the Trinity can enhance our faithfulness to the God depicted in the biblical story of salvation as well as enrich our understanding of the Christian life.

We should start by noting that the entire story of Jesus features a God who is interactively involved in our salvation as Father, Son, and Holy Spirit: Jesus is the Son sent by the Father to be conceived in Mary’s womb through the Spirit (Luke 1:35); the Spirit rested upon Jesus at His baptism as the Father expressed His love for the Son from heaven (Luke 3:21,22); the Son offered His life on the cross for our salvation “through the eternal Spirit” in faithfulness to the Father (Hebrews 9:14); the Father raised the Son from the dead “according to the Spirit of holiness” (Romans 1:4, KJV); Jesus ascended to the Father to receive the Spirit and to pour forth the Spirit upon us (Acts 2:33).

The entire story of Jesus from beginning to end is the story of how the triune God as Father, Son, and Spirit acted cooperatively to save us. Faithful to the story of Jesus, the entire New Testament speaks of God as Father, Son, and Holy Spirit (cf. Romans 15:30; 1 Corinthians 12:4–6; 2 Corinthians 13:14; Ephesians 1:17; 4:4–6; 2 Thessalonians 2:13; 1 Peter 1:2). Faithful to this story, we also name God in this same way in our worship, preaching, and witness.


We teach the doctrine of the Trinity to be faithful to the God depicted in the story of Jesus, the very heart of the biblical text. To teach this doctrine faithfully, however, we need to pay close attention to the biblical text. For example, the Old Testament makes it clear that there is but one Lord (Deuteronomy 6:4). Speaking in the first person singular (“I”), God said, “I am the Lord, and there is no other; apart from me there is no God” (Isaiah 45:5).

In Scripture, God speaks and acts toward humanity in the first person singular, as one God. God’s speech or action toward others is undivided, as the speech or action of the one God. So, when we say that God is one, we are not referring to something like a unified committee of people. The three persons are not three autonomous beings, each with a separate body or soul as the Mormons teach. This view of God is tritheistic (three gods) and not Trinitarian (one God eternally in three persons). Some may be tempted to view God tritheistically given the fact the modern term “persons” has commonly referred to autonomous or separate beings. But the oneness of God in the Bible means that the three persons of the Trinity are one in essence in the sense that they are inseparable personal agents of one divine life.

Yet, the Bible also indicates that God is eternally three. Not only does God speak to us in the first person singular in the Bible, God also converses within God’s own being as three, using the first person plural (“we”): “Let us make man in our image, in our likeness” (Genesis 1:26); or, "Come, let us go down and confuse their language” (Genesis 11:7). God’s actions toward us imply divine plurality even though these actions are undivided.

Though God speaks and acts toward us as one, God’s speaking and acting are also differentiated among three distinct agents, each of whom acts in a way that is appropriate to the divine person involved. For example, in the sending of the Son into the world (Luke 1:35), each of the three persons acts in a way that is distinctive or unique: The Father is not sent but sends the Son and the Spirit; the Son is sent to become flesh to image God and to die and rise for our salvation; the Spirit rests upon the Son for the accomplishment of His mission and to eventually indwell us and transform us into Christ’s image to the glory of the Father. This overall act is one undivided action of the one God. Yet, this action is also differentiated uniquely among three distinctly interactive agents and functions.


Some, like the ancient Arians or subordinationists, denied that God is eternally three by believing that only God the Father is truly divine (the Son and the Spirit being radically subordinated in nature to the Father). The Arians viewed the Son and the Spirit as exalted creatures but still finite (created in time) and, therefore, not divine. Denying the deity of Jesus in this way is impossible, however, because the Bible regards Jesus as the Savior of humankind (cf. Matthew 1:21; John 1:29; 1 Timothy 1:15; 2 Timothy 1:10), and grants Him the same worship given to God (John 20:28; Revelation 5:8–14).

The Old Testament is clear that only God can save or be worshiped. Hosea 13:4 allows for no exceptions: “You shall acknowledge no God but me, no Savior except me” (cf. Isaiah 45:21). Idolatry is thus defined as the worship of the mere creature rather than God the Creator (Romans 1:25). So, if only God saves and is to be worshiped, and Jesus saves and is worshiped, Jesus must be divine. We should also note that although Jesus is called the Savior in the New Testament, salvation is most often referred to as in or through Jesus. But this fact does not preclude His deity. In fact, it confirms Christ’s deity, for salvation is only possible in and through God. We do not have the power to build our own bridges to God. God must be that bridge, as well as the object toward which it leads. The only way to God is through God. Jesus is the way, truth, and life (John 14:6). Thus, Jesus’ role in salvation and our worship of Him as Savior and Lord necessitate our regarding Him as divine. We could never worship a mere creature as Savior and Lord or place ultimate trust or hope in a mere creature for salvation as we do with regard to Jesus.

Thus, biblical writers confessed Christ as Lord (1 Corinthians 12:3); as our “great God and Savior” (Titus 2:13); “the radiance of God’s glory and the exact representation of his being” (Hebrews 1:3). He was “with God” while being “God” from “the beginning” (or from all eternity, John 1:1); the eternal “First and the Last” (Revelation 1:17), coming forth from the Heavenly Father to reveal Him (John 1:18); and to impart the Spirit, which is a divine privilege (Genesis 2:7; John 20:22). He is the firstborn over all creation (Colossians 1:15) in His resurrection from the dead (1:18) and not by being created in time.

The Holy Spirit

The Holy Spirit sent forth from the Father through the Son is also divine, for the Spirit perfects the salvation given through the Son by sanctifying and glorifying the saints (2 Corinthians 3:18; 2 Thessalonians 2:13). If only God can save and the Spirit perfects salvation, the Spirit is also to be viewed as divine. God is Father, Son, and Holy Spirit.

Interaction Within the Trinity

Others, like the modalists, denied God’s eternal threeness by reducing the three persons to mere manifestations or modes of action of the one person of God. However, Father, Son, and Spirit in the Gospels lovingly interact with each other, which means that they cannot be reduced to mere temporary “roles” or “manifestations” of a single person (e.g. Luke 3:21,22; John 17:24).

Roles or manifestations cannot love each other or interact personally. Neither can Jesus temporarily lay aside His deity to interact as a mere human being with the Father. Jesus interacts as a divine Son with a divine Father, an interaction of two divine persons. Moreover, the Father loved and glorified the Son from before the time of creation (John 17:5,24).

The Son and the Spirit were present at creation functioning as mediating agents and cooperating together in carrying out the Father’s will (Genesis 1:2; John 1:3; Colossians 1:16; Hebrews 1:2). These three have lovingly interacted from before the beginning of time as distinct persons, not as different roles of a single person. Though inseparable from each other, the three persons of the Trinity are nevertheless eternally distinct from each other.

So, God is eternally both one and three. How can God be both? Traditionally, the Church has answered this by stating that God is one in one way and three in another. God is one in being or nature but three in person. Another way of saying this is that the one being of God exists eternally as a loving fellowship of three personal agents. That the one God has this complex capacity to interrelate as three distinct but inseparable persons is difficult for us to fathom. But let’s keep in mind that we are talking about an eternal being who is infinitely more complex than we are.


The complexity of the doctrine of the Trinity should not prevent us from teaching it. Teaching about the Trinity not only enhances our faithfulness to the God depicted in the story of Jesus, it can enrich the church’s view of the Christian life.

God does not just reign on high; God’s reign is near to our hearts and lives through Jesus and the gift of the Spirit (Matthew 12:28). What a difference it can make if we highlight the fact the God revealed in the story of Jesus is not a distant solitary ego but a circle of love that opened up to us in the Father’s sending forth of the Son and the Spirit into the world. God was willing, in the process, to be wounded by our sin to heal us.

By the Spirit we now commune with Jesus and, through Jesus, with His Heavenly Father. Salvation is not only forgiveness of sins but is also a transformative communion in God. Worship as well is not only to God but in God. The Father glorifies the Son and the Spirit-anointed Son glorifies the Father (John 17:1), while the Spirit glorifies both in and among us.

In worship and all of life, we become part of the circle of glory that involves the triune God. The same can be said of Christian witness, which is not only for God but also in God. The Father testifies of the Son and the Spirit-anointed Son of the Father (John 1:18; 8:18), while the Spirit testifies to both the Father and the Son in and among us.

We become part of the circle of witness that exists within the triune God. All of life is played out within the loving communion of Father, Son, and Holy Spirit. All of life is to be a participation in the dynamic exchange of love, glory, and witness that exists within God. Highlighting the Trinity in our teaching and preaching can only enrich the church’s understanding of God and of the entire Christian life in God.

Frank D. Macchia, D.Th., is professor of systematic theology at Vanguard University. He has recently published, The Trinity, Practically Speaking (Biblica, 2010).