The strangest claim in the Christian creed
The Christian Creed begins, I believe in one God. It then proceeds to name three: the Father, the Son who is Jesus Christ, and the Holy Spirit. To the outsider this looks like a contradiction. To the Christian it is the deepest truth there is. One God, three Persons.
The Catechism puts it carefully. The mystery of the Most Holy Trinity is the central mystery of Christian faith and life. It is the mystery of God in himself (CCC §234). It is not a puzzle to be solved. It is a reality to be received.
Why this is not three gods
Catholics, like Jews and Muslims, are monotheists. There is one God, eternal, uncreated, the source of all things. Hear, O Israel: the Lord our God, the Lord is one (Deuteronomy 6:4). Christianity does not back away from that line. It deepens it.
The Christian claim is that within the one God, from all eternity, there has been an unending life of love. The Father eternally begets the Son. The Father and the Son eternally breathe forth the Holy Spirit. Three Persons, one divine nature, one being, one God. It is not three parts that add up to a whole. Each Person is fully and entirely God.
Every analogy limps. The Trinity is not like anything else, because there is nothing else like God.
How Christians came to know this
The Trinity is not a doctrine the Church invented. It is what Jesus revealed.
- The Father. Jesus addresses God as Father, intimately and constantly. Our Father, who art in heaven (Matthew 6:9).
- The Son. Jesus speaks of Himself as one with the Father. I and the Father are one (John 10:30). At His Baptism the Father's voice declares, This is my beloved Son (Matthew 3:17).
- The Holy Spirit. At the Last Supper Jesus promises, The Holy Spirit, whom the Father will send in my name, he will teach you all things (John 14:26).
Before He ascends, Jesus gives the Church its mission in Trinitarian shape. Go therefore and make disciples of all nations, baptising them in the name of the Father and of the Son and of the Holy Spirit (Matthew 28:19). One name, three Persons. Every Catholic is baptised this way. Every Catholic prayer ends, Glory be to the Father, and to the Son, and to the Holy Spirit.
Why the Trinity matters
If God were a single solitary will, love would be something He decided to do. Because God is Father, Son, and Holy Spirit, love is what God eternally is. God is love (1 John 4:8) is not a slogan. It is a description of the inner life of God before anything was made.
This changes how Christians read everything. Creation is the overflow of an already loving God, not the project of a lonely one. The Cross is the Father giving the Son for us, and the Son freely going. The Church is brought to birth by the Holy Spirit at Pentecost. Heaven is being drawn into the life of love that was always going on.
Bishop Mark Davies, on the night of Pope Leo XIV's election, drew attention to the Cross carried out onto the balcony of St Peter's before the new Pope appeared.
It seemed significant that before we caught sight of our new Pope, we saw first the Cross of Christ carried onto the balcony of Saint Peter's. For the Pope always stands before the world as a witness to Christ and to the victory of His Cross.
Bishop Mark Davies, Pastoral Letter on Welcoming Pope Leo XIV with Great Joy
The Cross is the Trinity in action. Father, Son, and Spirit are not three masks the one God puts on. They are the eternal life into which Christians are drawn through the Cross.
How the Trinity shapes Catholic life
You meet the Trinity every time a Catholic crosses themselves. The hand moves from forehead to heart to shoulders, naming Father, Son, and Holy Spirit. It is the smallest creed. Children are taught it before they can read.
The Trinity also shapes the Mass.
- Mass begins, In the name of the Father, and of the Son, and of the Holy Spirit.
- The Eucharistic Prayer is offered through Him, with Him, in Him, that is, the Son, in the unity of the Holy Spirit, to the Father.
- The blessing at the end is given in the name of all three.
At Shrewsbury Cathedral, designated one of two pilgrim churches for the Jubilee Year 2025, every Mass is offered into this Trinitarian shape. The 175 years of this diocese, from Bishop James Brown and his first 26 priests in 1851 to Bishop Davies today, have been Trinitarian from beginning to end.
Your next step
If the Trinity feels too large to grasp, that is the right reaction. Mystery is not what you have not yet understood; mystery is what is too rich ever to be exhausted. The Catechism's chapter on the Trinity, paragraphs 232 to 267, is freely available online and reads more clearly than people expect.
Or come to a Sunday Mass at Shrewsbury Cathedral, 11 am, and listen for the Creed. Hear how the one God is named three times, and join the line of Christians who have prayed those words since the fourth century.
