Many years ago, I attended a parish anniversary that happened to fall on Trinity Sunday.

The homilist spent about a minute on the Trinity, the central mystery of the Christian faith. In effect, he dispensed with it as an impenetrable mystery beyond anyone’s power of understanding. He then launched into a string of charming stories drawn from the history of the parish.

 Everyone enjoyed his homily, but in fact it shortchanged the congregation, consisting of Christians baptized in the name of the Triune God. It also did not do full justice to the parish as part of the Church, described by the Second Vatican Council as a people “gathered together in the unity of the Father and the Son and the Holy Spirit” (Lumen Gentium, 4; Compendium of the Catechism of the Catholic Church, 153).

Indeed, the Trinity is a mystery that sheds light on every aspect of our faith and lives, as we shall see with greater clarity as this series of articles progresses.

In my May column, I tried to show how one can arrive at the existence of God and even some of his attributes through reason. While it is true that hints of God’s Trinitarian love are found in creation and in the Old Testament, the mystery of the Trinity can only be known because the one God has revealed himself as a Trinity of Persons. This mystery was revealed when God’s Son assumed our humanity and entered into human history.

The Trinity is the most sublime and central mystery of our faith. Far from being a mere puzzle or an irrational assertion, the mystery of the Trinity both exceeds and elevates the powers of reason. As a result of God’s self-revelation in and through Jesus Christ, we can come to a much clearer understanding of who God is — without, of course, attaining full knowledge of his infinite majesty and glory.

God the Father was revealed through Christ’s life, teaching and saving deeds. Jesus taught us that God the Father is the beneficent Creator. Recall, for instance, his words about the birds of the air and the lilies of the field (See Mt 6:26- 28). Even more so, Jesus showed us his relationship with the Father, which we see when Jesus becomes absorbed in prayer. We hear it in Jesus’ teaching when he tells us that he came from the Father and is returning to him.

We share in Jesus’ relationship with God the Father through his loving obedience to the Father’s saving will, expressed by the love Jesus embraced on the cross. Jesus also revealed the Holy Spirit. From Scripture we learn that Jesus was conceived by the power of the Holy Spirit and that the Spirit hovered over him at his baptism and at the Transfiguration. After his death and resurrection, Jesus breathed the Holy Spirit upon the Apostles, empowering them to forgive sins. Finally, the Holy Spirit descended upon the Apostles and the Virgin Mary at Pentecost.

Reflecting on this, the Church definitively teaches that the Father eternally generates the Son and that the Son is eternally generated by the Father. The living, eternal bond of love between the Father and Son is the Person of the Holy Spirit (Compendium, 48).

This helps us understand what is meant when the Church expresses its Trinitarian faith: “One God in three Persons.” Notice that Father, Son and Holy Spirit are not merely three names for God or merely three ways in which the one God might appear. Nor should we think of the Trinity as three gods cobbled together in a corporate partnership.

There really is only one God, yet with three distinct Persons (the Father is not the Son and the Son is not the Father, etc.). The three Persons of the Trinity possess completely and co-equally the divine nature. They are three identifiable Persons, each fully God in a manner that is distinct yet related to the others (see U.S. Catholic Catechism for Adults, 52).

Because the Trinity is so great a mystery, we may be tempted to side with the aforementioned homilist who decided to gloss over this teaching in favor of sharing personal anecdotes. However, to do so would miss the most beautiful teaching of the New Testament: God is love. The complete self-giving of the three Persons of the Trinity, each to the others, reveals to us a love beyond all telling, a love that the Trinity lavished upon us in creation and redemption, and a love we are called to share through baptism.

It is a passionate love but not a self-seeking love, described so beautifully in Pope Benedict XVI’s first encyclical, Deus Caritas Est (God is Love). This is the love that illuminates everything we believe in and hope for as Catholic Christians. It is the mystery of a communion of love that gives joy and meaning to our lives as we seek union with God and unity with one another.

I am reminded of a particularly challenging homily I once had to give. One Trinity Sunday as I arrived at church, I learned to my complete surprise that I was scheduled to celebrate the children’s Mass. It was immediately clear that my prepared homily would not do. But as the moment approached, I had no clue how to present this sublime mystery in a vocabulary the children would understand.

I was praying to the Holy Spirit for help when I blurted out, “Who knows how to make the Sign of the Cross?”

Everyone could. I then asked, “Is there one God or three?” A bright little girl answered, “Oh, Bishop, there’s only One God but he has three Persons.”

“Out of the mouths of babes,” I thought as I pressed on. “Well, who are the three Persons?” I asked. The same little girl said, “Father, Son and Holy Spirit” and added, “Bishop, everyone knows that!”

1. The mystery of the Holy Trinity is the central mystery of the Christian faith and life. How would you describe the doctrine of the Trinity to others?

2. At several times in his public ministry beginning with his baptism by St. John the Baptizer, Jesus revealed the mystery of the Trinity to believers. Review some of these passages from the New Testament, including Mt 3: 13-17, Mt 11: 25-30, Jn 5: 16-47 and Chapter 16 of the Gospel of St. John, among others.

3. The sacrament of confirmation is understood as the second sacrament of initiation after baptism. In receiving the Holy Spirit, believers are called to greater contemplation of the mystery of the Triune God – Father, Son and Holy Spirit. If you have been confirmed, discuss what the experience was like.What should be the result of one’s deeper understanding of the faith which comes from confirmation?

4. How can we discover the presence of the Trinity in our lives?