This year, the Nicene Creed turns seventeen hundred years old. Christ’s outpouring of the Spirit at Pentecost has great significance for the church’s doctrinal teaching throughout the ages, including in the Nicene Creed. Paul writes: “And he gave some, apostles; and some, prophets; and some, evangelists; and some, pastors and teachers; for the perfecting of the saints, for the work of the ministry, for the edifying of the body of Christ” (Eph. 4:11–12 KJV). Through the outpouring of the Spirit, Christ gave the gift of pastors and teachers, those uniquely gifted at preaching and teaching the Word of God. Christ gave these gifts for perfecting, equipping, and building the body of Christ. The gifts of Christ extend from Pentecost to the present day and beyond, to the consummation. Every single faithful pastor and teacher in the history of the church constitutes Christ’s gifts to the church.

Christ’s gifts bring two relevant and vital truths to our hearts and minds. First, as we note the seventeen-hundredth anniversary of the Council of Nicaea, which met May through July of AD 325, we can class the Nicene fathers as part of Christ’s gifts to the church. Second, while Scripture is our chief authority, it is not our only authority. We can appeal to the authority of tradition so long as Scripture remains our lone chief authority—so long as we submit the opinions of ancient writers to “no other but the Holy Spirit speaking in the Scripture,” we are on safe ground (Westminster Confession of Faith 1.10). Given these two presuppositions, we can ask some helpful questions: Why was the Council of Nicaea necessary? What scriptural truths were false teachers promoting? How did the church fathers of Nicaea defend the truth? Answering these questions allows us, the church in the present, to continue to proclaim the faith that was once delivered to the saints—the truth that Jesus is God in the flesh who came to save sinners.

Denying the Truth

For thousands of years God promised that he would come in the person of his Son to redeem his people from their sin. God progressively unfolded this promise throughout redemptive history until Christ was born. John powerfully captures the truth of the incarnation when he writes: “In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God” (John 1:1–2). The Son is fully God, but wonder of wonders, “The Word became flesh and tabernacled among us, and we have seen his glory, glory as of the only begotten from the Father, full of grace and truth” (John 1:14, translation mine). Scripture clearly teaches that the Son of God is God and that he became a human being. Despite the historical reality of Christ’s incarnation and the perspicacity of God’s Word, the serpent still slithers through the church and asks, “Yea, hath God said . . . ?” (Gen. 3:1 KJV). False teachers in the apostolic church denied the doctrine of the incarnation. The Apostle John instructed the church on how to discern false from true teachers: “By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God” (1 John 4:2). In other words, there were those who denied the incarnation of the Son of God.

By the third century, false teaching from a bishop by the name of Arius (ca. 250–336) was spreading. Arius believed that Jesus was not fully equal with God. Instead, he believed that the Son of God was the highest of all creatures; when the Scriptures, for example, state that Jesus is the “begotten” of the Father (John 1:14 KJV), Arius claimed beget means to create. If the Father begot the Son, then there was a time when the Son did not exist. Bishop Alexander of Alexandria (d. ca. 326) got wind of Arius’s teaching and called a synod in Alexandria in 317 that condemned Arius’s views. Arius appealed his condemnation to Eusebius of Nicomedia (d. 341) and controversy ensued. Emperor Constantine (272–337) heard of the dispute and called for a council to resolve the conflict. The issue before the Council of Nicaea was to defend the biblical truth regarding the deity of the Son of God.

Defending the Truth

While there were other doctrinal issues in play, the Council’s deliberations focused upon the question of whether Jesus was of “like substance” (homoiousias) with the Father, which was the view of Arius, or whether he was of the “same substance” (homoousias) with the Father. Was the Son, in other words, fully and completely God or was he only merely like God?

Some might initially object to the introduction of terms foreign to the Bible. Why invoke the term homo-versus homoiousias? Why not simply rest on the terms used in Scripture? The Arians were willing to say that the Son of God was like the Father in every way but argued that because he was “begotten” by the Father, it meant he had a genesis or origin. The Nicene fathers, then, introduced extra-biblical terminology to define what various passages of Scripture meant and to preclude Arian false teaching. This truth came home to me in an unforgettable way when I was in seminary. I once asked one of my professors how an interview with the trustees went. He smiled and said it went very well. Why? He said, “They asked me if I believed in substitutionary atonement, and I said, ‘Yes I do.’ What they don’t know is that I have redefined what substitutionary atonement means.” J. Gresham Machen documented this phenomenon in Christianity and Liberalism when he said that theological liberals use biblical language, but they redefine it, empty it of truth, and then boldly appeal to the Word of God. My professor did this with the seminary trustees, and the Arians also did this at the Council of Nicaea.

When the Council completed the creed, they made a number of statements that carefully guarded the deity of Christ and traced the teaching of divine revelation. The creed states that the Son of God was “begotten of the Father, only-begotten, that is, of the substance of the Father, God of God, Light of Light, true God of true God, begotten not made, of one substance [homoousion] with the Father.” The first thing we observe is that the creed traces biblical language when it says that the Son was “begotten of the Father.” John’s gospel makes this claim four times: “And the Word was made flesh, and tabernacled among us, and we behold his glory, the glory as of the only begotten of the Father” (John 1:14, translation mine); “No one has ever seen God; the only begotten God, who is at the Father’s side, he has made him known” (John 1:18, translation mine); “For God so loved the world, that he gave his only begotten Son” (John 3:16 KJV); and “Whoever does not believe is condemned already, because he has not believed in the name of the only begotten Son of God” (John 3:18, trans. alt.). But because the Arians also affirmed the term begotten but redefined it, the creed specifies that the Son is “begotten not made.” In other words, the creed is saying, “We do not mean what the Arians mean when they say begotten.” The creed affirms that the Son is eternally begotten; in other words, there is no time when the Son did not exist: “And those who say ‘There was a time when he was not,’ and, ‘Before he was begotten he was not,’ and that, ‘He came into being from what is not,’ . . . these the catholic and apostolic church anathematizes.” Nicaea states that the Son is eternally the Son.

A second feature of the creed’s statement is that it affirms that the Son of God is “of the substance of the Father” and it invokes the technical term homoousias: the Son is consubstantial, or the same exact “stuff” of the Father. In the later language of the Chalcedonian Definition (451), the Son of God is “truly God.” The Nicene Creed affirms this point by saying that the Son is “God of God, Light of Light, true God of true God.” An initial reading of these statements may lead some to the hasty conclusion that the Son derives his deity from the Father because he is “Light of Light” rather than simply saying that he is eternal light all on his own. To address this issue, we must consider two theological truths concerning the doctrines of God and the Trinity. First, the fathers of Nicaea affirmed the doctrine of divine simplicity as it pertains to the being of God. The Westminster Confession, for example, teaches this truth when it states that God is “without body, parts, or passions” (2.1). God has no parts; he is not a composite being like a human, that has arms, legs, a soul, intellect, will, affections, etc. All that is in God is God. The Westminster Confession coordinates the doctrine of divine simplicity with the doctrine of the Trinity when it states that “in the unity of the Godhead there be three persons, of one substance, power, and eternity” (2.3). In other words, all three persons, Father, Son, and Holy Spirit, share the same divine substance. Factoring the “Light of Light, true God of true God” statement in light of divine simplicity means the Son is fully God because he is of the same substance as the Father. We must coordinate the “Light of Light, true God of true God,” however, to the three persons of the Trinity.

All three persons of the Godhead share the same divine substance. Medieval theologian Anselm of Canterbury (1033–1109) helpfully explains that we stress the unity of the Godhead to highlight that all three persons are God. However, we must never push the unity at the expense of harming the three persons of the Trinity. In other words, if we emphasize the unity of the Godhead at the expense of the three persons, then we fall into the error of unitarianism. Three distinct persons collapse into the unity of the Godhead, and we lose the scriptural doctrine of the Trinity. When the Nicene Creed, therefore, says that the Son is “Light of Light, true God of true God,” it affirms that the Son is at the same time fully God and he is also eternally distinctly the Son. The Father and Son are distinct persons. To put this in terms of the Athanasian Creed (fifth or sixth century), the three persons of the Godhead are all God and Lord, yet “the Father was neither made nor created nor begotten from anyone. The Son was neither made nor created; he was begotten from the Father alone. The Holy Spirit was neither made nor created nor begotten; he proceeds from the Father and the Son.” That is, all three persons are God, yet the Father is neither the Son nor the Spirit; the Son is neither the Father nor the Spirit; and the Spirit is neither the Father nor the Son. We must always preserve the unity of the Godhead and the reality of the three persons.

When the Nicene Creed says that the Son is “Light of Light, true God of true God,” it once again traces the lines of divine revelation. Recall Jesus’s words: “For as the Father has life in himself, so he has granted the Son also to have life in himself” (John 5:26). In the words of John Calvin’s Genevan Catechism (1545), “The Lord Jesus who was begotten of the substance of the Father, and is of one essence with the Father, is by the best title called the only Son of God, because he alone is Son by nature” (Q. 22). The Father communicates his essence to the Son. Calvin elsewhere writes, “The Father is the fountain and origin of the deity” (Institutes, 1.8.7, 23, 25). Or in the words of Zacharias Ursinus, the author of the Heidelberg Catechism (1563):

The Father is the first person, and, as it were, the fountain of the divinity of the Son and Holy Spirit, because the Deity is communicated to him of no one; but he communicates the Deity to the Son and Holy Spirit. The Son is the second person, because the Deity is communicated to him of the Father, by eternal generation.

The Westminster Confession sums up these Nicene constructions when it states: “The Father is of none, neither begotten, nor proceeding; the Son is eternally begotten of the Father; the Holy Ghost eternally proceeding from the Father and the Son” (2.3).

The Nicene Creed Today

The German poet Johann Wolfgang von Goethe (1749–1832) once wrote, “What you have as heritage / Take now as task.” In other words, we should not look at the Nicene Creed as if it were an antiquated museum relic. Rather, the creed rightly explains the deity of the Son and also helps the church to understand the doctrine of the Trinity. The Nicene tradition is now our task—we must pass on this doctrinal heritage to future generations. We must faithfully herald the message of Scripture so beautifully captured in John 1:1: “In the beginning was the Word, and the Word was with God, and the Word was God.” With Paul we must say that the “fullness of deity dwells bodily” (Col. 2:9). We can both worship Christ and rejoice in knowing that Jesus, the Son of God and the Son of Man, saved sinners like us. We can thank our triune God and celebrate the gifts that Christ has given to the church on this, the seventeen-hundredth anniversary of the Council of Nicaea.

The author, an OP minister, is the Harriett Barbour Professor of Systematic and Historical Theology at Reformed Theological Seminary in Jackson, Mississippi. New Horizons, October 2025.