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The Trinity: one God in three persons

Amen · 8 min read

The doctrine of the Trinity is one of the deepest and at the same time most central teachings of the Christian faith. It affirms that there is one God, who is eternally Father, Son and Holy Spirit: three distinct persons, equal in divinity, sharing one essence. For many, the Trinity seems a difficult or abstract concept. Yet it is not the speculation of theologians, but the way God himself has revealed himself in the history of salvation.

The word “Trinity” does not appear in the Bible, just as the word “incarnation” does not. It is a term the Church used to sum up what Scripture teaches. In this article we explore the biblical basis of this doctrine, how the early Church formulated it, the errors it rejected and why the Trinity matters so much for the Christian life.

“Hear, O Israel: The Lord our God is one Lord.”

Deuteronomy 6:4

1. There is one God

The starting point is monotheism. Israel lived surrounded by peoples who worshipped many gods, and God revealed clearly that he alone is God. The prayer known as the Shema, in Deuteronomy 6:4, proclaims that the Lord is one. Isaiah repeats the message: “I am the Lord, and there is none else, there is no God beside me” (Isaiah 45:5).

The New Testament confirms this truth. Jesus quoted the Shema as the first commandment, and Paul wrote that to us there is but one God (1 Corinthians 8:6). The Trinity is not belief in three gods, but in one God.

2. The Father is God

The Bible calls God Father on many occasions. Jesus prayed to the Father, taught his disciples to say “Our Father” and spoke constantly of his relationship with him. Paul begins his letters wishing grace and peace “from God our Father”. The divinity of the Father has never been a matter of controversy in the Church.

3. The Son is God

The New Testament clearly affirms that Jesus Christ is God. John writes: “the Word was God” (John 1:1). Thomas, on seeing the risen Jesus, exclaimed: “My Lord and my God” (John 20:28), and Jesus accepted that confession. Paul says that in Christ dwells all the fulness of the Godhead bodily (Colossians 2:9) and calls him “the great God and our Saviour Jesus Christ” (Titus 2:13). Hebrews presents the Son as the brightness of God’s glory and the express image of his person (Hebrews 1:3).

Moreover, Jesus did things only God can do: forgive sins, receive worship, give life and judge the world. At the same time, the Son is distinct from the Father: he prays to the Father, is sent by the Father and does his will. For more, read our article Who is Jesus Christ according to the Bible?

4. The Holy Spirit is God

The Holy Spirit is not an impersonal force but a divine person. In Acts, Peter tells Ananias that he has lied to the Holy Spirit and, in the next sentence, that he has not lied to men but to God (Acts 5:3-4). The Spirit has divine attributes: he is present everywhere (Psalm 139:7), searches the deep things of God (1 Corinthians 2:10) and took part in creation (Genesis 1:2).

He also acts as a person: he teaches, guides, comforts, intercedes, can be grieved and distributes gifts as he wills. Jesus called him “another Comforter” (John 14:16), that is, someone like himself, distinct from the Son and the Father. Go deeper in our pages on the Holy Spirit and his gifts.

5. The three persons together in Scripture

In several passages the three persons appear together. At Jesus’ baptism, the Son comes up out of the water, the Spirit descends like a dove and the Father speaks from heaven (Matthew 3:16-17). In the Great Commission, Jesus commands baptism “in the name of the Father, and of the Son, and of the Holy Ghost” (Matthew 28:19). Notice that it says “in the name”, singular, not “in the names”, expressing the unity of the three persons.

Paul closes his second letter to the Corinthians with a Trinitarian blessing: “The grace of the Lord Jesus Christ, and the love of God, and the communion of the Holy Ghost, be with you all” (2 Corinthians 13:14). In Ephesians 4:4-6 he speaks of one Spirit, one Lord and one God and Father. And Peter greets believers elect according to the foreknowledge of God the Father, through sanctification of the Spirit, unto obedience and sprinkling of the blood of Jesus Christ (1 Peter 1:2).

6. Hints in the Old Testament

Although the Trinity is revealed clearly in the New Testament, many Christians have seen hints in the Old. In Genesis 1:26 God says: “Let us make man in our image.” The Spirit of God moved upon the waters at creation. There is also the mysterious figure of the Angel of the Lord, who speaks as God. The prophets announce a Messiah called “The mighty God” (Isaiah 9:6) and a Servant upon whom the Spirit rests. These passages do not prove the Trinity on their own, but they are read in a new light from Christ.

7. The formulation of the early Church

During the first centuries, Christians worshipped the Father, the Son and the Holy Spirit, baptised in the name of the three and prayed in that faith. But when teachings arose that questioned the full divinity of the Son or of the Spirit, the Church had to express its faith more precisely.

Arius, a priest in Alexandria, taught that the Son was the first and highest creature, but not eternal nor equal to the Father. In response, the Council of Nicaea in 325 affirmed that the Son is “God from God, Light from Light, true God from true God, begotten, not made, of one being with the Father”. The Council of Constantinople in 381 expanded the creed, affirming the divinity of the Holy Spirit, “the Lord, the giver of life”, who with the Father and the Son is worshipped and glorified.

This Niceno-Constantinopolitan Creed is today one of the texts that most unites Christians around the world: it is confessed by the Catholic Church, the Orthodox churches, the Anglican and Lutheran churches and many other Protestant churches. It is an important foundation of ecumenical dialogue, although Catholics and Orthodox still discuss a phrase added in the West about the procession of the Spirit.

8. Errors the Church rejected

Tritheism: believing in three separate gods. The Bible teaches one God. Modalism: teaching that God is a single person who appears successively as Father, then as Son and then as Spirit, like an actor changing masks. This cannot explain why at Jesus’ baptism the three persons act at the same time, or why the Son prays to the Father. Arianism: claiming that the Son is a created being, inferior to the Father. Denying the personhood of the Spirit: regarding him only as an energy or influence.

Trinitarian faith holds two truths in balance: the unity of God and the real distinction of the three persons.

9. Analogies and their limits

Throughout history, comparisons have been used to explain the Trinity: water, which can be liquid, solid or vapour; the sun, with its light and heat; a man who is at once father, son and husband; or the three-leaf clover that, according to tradition, Saint Patrick used in Ireland. These images can help awaken reflection, but all are imperfect. Some resemble modalism, and others separate the persons too much.

The Trinity is a mystery, not in the sense of something contradictory, but of a reality that exceeds our full understanding. It makes sense that the infinite Creator should be greater than the human mind can grasp. Augustine of Hippo, who wrote a whole work on the Trinity, acknowledged that we speak of it not in order to say everything, but so as not to remain silent.

10. Why the Trinity matters

God is love from eternity. If God were a single solitary person, whom did he love before creating the world? The Trinity reveals that love exists eternally in God: the Father loves the Son, the Son loves the Father, in the communion of the Spirit. That is why John can say that “God is love” (1 John 4:8).

Salvation is the work of the triune God. The Father sends the Son out of love; the Son gives his life to save us; the Holy Spirit applies that salvation to our hearts and makes us children of God. Paul says that God sent forth the Spirit of his Son into our hearts, crying “Abba, Father” (Galatians 4:6).

Christian prayer is Trinitarian. We pray to the Father, through the Son, in the Holy Spirit. We do not pray to a distant God; we are brought into the very relationship of love that exists in God.

Community reflects God. The unity in diversity of the Trinity is a model for the Church, marriage and the family: distinct persons, of equal dignity, united in love. Jesus prayed that his followers would be one, as he and the Father are one (John 17:21).

11. Living the Trinitarian faith

Every time a Christian is baptised, makes the sign of the cross, recites the creed, pronounces the final blessing or sings “Glory be to the Father, and to the Son, and to the Holy Spirit”, he or she confesses the Trinitarian faith. But beyond words, living this faith means trusting the love of the Father, following Jesus Christ and letting ourselves be led by the Holy Spirit every day.

Prayer

Glory to you, Father, who created us and love us. Glory to you, Son, who became man, died and rose again to save us. Glory to you, Holy Spirit, who dwell in us and give us life. Holy Trinity, one God, we worship you and give you thanks. Grant that we may live in your love and that your Church may be one, as you are one. Amen.