The Trinity

The LORD is one

The last lesson asked what God is like. This one turns to the most distinctive thing Christians say about him. It begins where Israel began, with the words every faithful Jew prayed morning and evening.

Hear, O Israel: The LORD our God, the LORD is One.

Deuteronomy 6:4

There is one God, and only one. "I am the LORD, and there is no other; there is no God but Me," he says through Isaiah (Isaiah 45:5). The New Testament never softens this. Writing to Christians in a city of many temples, Paul says that an idol is nothing and there is no God but one, and then adds:

yet for us there is but one God, the Father, from whom all things came and for whom we exist. And there is but one Lord, Jesus Christ, through whom all things came and through whom we exist.

1 Corinthians 8:6

Many interpreters hear the Shema echoing here, its ‘God’ and ‘LORD’ now naming the Father and Jesus Christ within one confession. Paul is not adding a second god beside the first. He is confessing the Father and the Lord Jesus together within the one God of Israel.

Father, Son and Holy Spirit

The New Testament speaks of the Father, the Son and the Spirit each as God. John's Gospel opens, "In the beginning was the Word, and the Word was with God, and the Word was God" (John 1:1). Thomas says to the risen Jesus, "My Lord and my God!" (John 20:28). Hebrews applies a psalm to the Son: "Your throne, O God, endures forever and ever" (Hebrews 1:8). And when Ananias chose "to lie to the Holy Spirit" (Acts 5:3), Peter told him, "You have not lied to men, but to God!" (Acts 5:4).

Yet the three are not simply three names for one person. At Jesus' baptism the Son comes up from the water, the Spirit descends like a dove, and the Father's voice says, "This is My beloved Son, in whom I am well pleased!" (Matthew 3:17). The Son prays to the Father, and the Father sends "another Advocate" (John 14:16). And the three are named together.

Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit,

Matthew 28:19

Not ‘names’ but one ‘name’. Paul's blessing has the same shape: "The grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit be with all of you" (2 Corinthians 13:14). The Son's deity is explored further in Truly God and truly man, and the Spirit's in Who the Holy Spirit is.

The word ‘Trinity’ is not in the Bible. Tertullian, writing in Latin early in the third century, was among the first to use it (trinitas), describing Father, Son and Spirit as three persons of one substance Tertullian, Against Praxeas. But a new word is not a new belief. Scripture says three things: God is one; the Father, the Son and the Spirit are each God; and the three are distinct. The doctrine of the Trinity simply refuses to let go of any of them.

What the church confessed, and what it refused

Some teachers made the mystery tidier by dropping one of those truths, and in answering them the church learned to speak more carefully. In the third century Sabellius, wanting to protect God's oneness, taught that the one God appears now as Father, now as Son, now as Spirit, like one actor changing masks. This is called modalism. But then the voice at the baptism and the prayers of Jesus become God talking to himself. In the fourth century Arius, a presbyter of Alexandria, wanting to protect God's uniqueness, taught that the Son was the first and greatest of God's creatures. But John says, "Through Him all things were made" (John 1:3), which puts the Son on the Creator's side of the line, not the creature's. Tritheism, the belief in three gods, fails in the opposite direction, against the Shema itself.

Jesus said, "I and the Father are one" (John 10:30). The Greek word for ‘one’, hen (ἕν), is neuter, one thing rather than one person, and the verb is plural: we are. Augustine saw both errors answered in that short sentence: "In that He says, one the Arian, in we are the Sabellian, is answered" Augustine.

The Council of Nicaea in 325 confessed that the Son is "Begotten, not made, Being of one substance with the Father", using the Greek word homoousios. The Council of Constantinople in 381 completed the creed by confessing the Holy Spirit as "The Lord and giver of life", who "with the Father and the Son together is worshipped and glorified" The Nicene Creed. The later Athanasian Creed puts it with great care: "we worship one God in Trinity, and Trinity in Unity; Neither confounding the Persons: nor dividing the Substance" The Athanasian Creed.

This is also why the familiar analogies disappoint. Water, ice and steam picture one substance taking different forms in turn, which is modalism. An egg's shell, white and yolk are three parts making up a whole, but each person of the Trinity is fully God, not a third of God. Augustine searched long for images, such as the lover, the beloved and the love between them, and confessed that every one falls short Augustine, On the Trinity. The Trinity is beyond our understanding, but it is not a contradiction: God is one in being and three in persons, not one and three in the same respect.

"And the Son"

One phrase still divides the churches. The creed of 381 confesses that the Spirit proceeds from the Father, echoing Jesus' words about "the Spirit of truth who proceeds from the Father" (John 15:26). From about the sixth century, Latin-speaking churches began to add filioque, ‘and the Son’, and the addition gradually spread through the whole Western church. The 1662 Book of Common Prayer, for instance, has "Who proceedeth from the Father and the Son".

The Catholic Church and most Protestant churches, heirs of the Western tradition, confess that the Spirit proceeds from the Father and the Son. They point out that he is called "the Spirit of His Son" (Galatians 4:6) and that Jesus says, "I will send Him to you" (John 16:7). Augustine reasoned that "the Holy Spirit is not the Spirit of one, but of both" Augustine. The West meant to guard the Son's full equality with the Father.

The Orthodox churches keep the original wording of 381. They hold that the Father is the one source of the Son and the Spirit, and that the Son's sending of the Spirit into the world must be distinguished from the Spirit's eternal coming forth from the Father. The Byzantine commentator Theophylact writes on John 15:26: "To proceed is not the same as being sent, but is the essential nature of the Holy Ghost, as coming from the Father" Theophylact. They also object that a creed confessed by a council of the whole church was changed by one part of it alone.

Both traditions confess the Spirit as fully God, worshipped together with the Father and the Son, and the question is still discussed in dialogue between the churches. Some Eastern Fathers spoke of the Spirit proceeding from the Father through the Son, and that phrase is often mentioned as a place where the two sides might meet.

The Trinity is not a puzzle for specialists but the shape of the gospel. Jesus prayed to the Father, "You loved Me before the foundation of the world" (John 17:24). So "God is love" (1 John 4:8) is not something God became when he made us to love; it is who he has always been. And our salvation has the same shape: "For through Him we both have access to the Father by one Spirit" (Ephesians 2:18). For more, see What is the Trinity?, Is Jesus God? and Who is the Holy Spirit?.

Practice