The Holy Trinity

The Catholic Church teaches that there is only one God. Within the one divine Being are three really distinct Persons: the Father, the Son, and the Holy Spirit.

“Person” and “being” answer different questions. Being concerns what God is; Person concerns who God is. God is one “what” and three “whos.” This language does not completely explain God, but it prevents us from confusing unity with sameness of Person.

It cannot—and that is the point. The Trinity was never meant to be addition.

Three Persons does not mean three separate beings stacked together. It means one God who eternally exists, complete and undivided, as Father, Son, and Holy Spirit—not one at a time and not as parts of a whole.

Numbers are being used in different respects: one answers how many Gods there are; three answers how many Divine Persons there are. God is not a quantity assembled from smaller quantities.

Although the word Trinity does not appear in the Bible, the truths expressed by the doctrine do.

There is only one God

The Father is God

Jesus speaks of God the Father, upon whom the Father has set His seal (John 6:27). The New Testament repeatedly identifies the Father as God.

The Son is God

John teaches that the Word was with God and was God, and that the Word became flesh (John 1:1, 14). Thomas addresses the risen Jesus as “My Lord and my God” (John 20:28).

The Holy Spirit is God

In Acts 5:3–4, Peter describes lying to the Holy Spirit as lying to God. The Spirit acts personally: He teaches, speaks, sends, guides and can be grieved.

The three Persons are distinct

At Jesus’ baptism, the Son is in the water, the Spirit descends, and the Father speaks from heaven (Matthew 3:16–17). Jesus promises that He will ask the Father to send another Advocate, the Spirit of truth (John 14:16–17).

Named together as one

Jesus says “name” in the singular while naming three Persons. The baptismal command holds together the unity of God and the distinction of Father, Son and Holy Spirit.

The three Persons are not different masks worn by God. Their distinction is real and eternal.

• The Father is not the Son or the Holy Spirit.
• The Son is not the Father or the Holy Spirit.
• The Holy Spirit is not the Father or the Son.
• Each Person is fully and equally God.
• The three Persons possess the same one divine nature, power, eternity and glory.

The Persons are distinguished by their eternal relationships. The Father eternally begets the Son. The Son is eternally begotten, not made. The Holy Spirit eternally proceeds. These relationships do not divide God or make one Person older, stronger or more divine than another.

The Shield of the Trinity is a traditional diagram summarising several essential statements about the Trinity.

The diagram correctly shows that each Person is God and that the Persons are distinct. It is a useful summary, but it does not explain every aspect of Trinitarian theology or remove the mystery.

The Church did not invent the Trinity in the fourth century. Christians already worshipped the Father, Son and Holy Spirit, baptised in their name and confessed Jesus as Lord. Controversies forced the Church to define its inherited faith more precisely.

The Council of Nicaea — AD 325

Nicaea responded especially to Arius, who taught that the Son was created and was not eternal in the same way as the Father. The Council confessed the Son as “begotten, not made” and consubstantial—of the same divine substance—with the Father.

The Council of Constantinople — AD 381

Constantinople confirmed the Nicene faith and expanded the Creed’s confession of the Holy Spirit as Lord and giver of life, worshipped and glorified with the Father and the Son.

The Creed commonly recited at Sunday Mass is called the Nicene-Constantinopolitan Creed because its received form reflects these first two ecumenical councils.

Created things can reflect something of their Creator, but no created example perfectly matches the Trinity.

• Water as ice, liquid and vapour can suggest one substance in different states, but it can imply one Person changing forms.
• An egg with shell, white and yolk suggests three parts forming one object, but each Divine Person is fully God.
• A three-leaf clover also suggests that each Person is only one part of God.
• One person acting as parent, child and worker describes roles, not three distinct Persons.

Analogies can begin a conversation, but they must not replace the Church’s careful language. The Trinity is unique; nothing else exists exactly as God exists.

The Trinity is not an optional puzzle added to Christianity. It tells us who God is and shapes the whole Christian life.

• Creation: the one God creates through the Son in the Holy Spirit.
• Salvation: the Father sends the Son, who becomes man for us, and the Father and Son give the Holy Spirit.
• Prayer: Christians ordinarily pray to the Father, through the Son, in the Holy Spirit.
• Baptism: Christians are baptised into the singular name of the Father, Son and Holy Spirit.
• The Mass: the Church offers worship to the Father through Christ in the unity of the Holy Spirit.
• Christian love: God is eternally a communion of life and love, and grace draws us into communion with Him and with one another.

Without the Trinity, the Gospel changes. If the Son were not truly God, He could not reveal the Father as He does. If the Holy Spirit were not God, He could not give us participation in divine life. Christian salvation is the work of the one Triune God.