Trinity Sunday 
Homily

By the Most Rev Timothy Costelloe SDB
Archbishop of Perth

St Mary’s Cathedral, Perth
Sunday 11 June, 2017

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One of the joys of being a bishop is the opportunity I have to celebrate the Sacrament of Confirmation in our parishes on a number of occasions each year.  While of course, due to the large number of parishes we have in our archdiocese, it is not possible for the bishops to be present at every Confirmation ceremony throughout the year, it is nevertheless important that Confirmation be celebrated by a bishop if possible.  This is the long standing tradition of our Church and, among other things, points to the important truth that to belong to the Church means more than just belonging to the local parish, important though that is.  We know that the bishop is meant to be the great symbol of unity for all Catholics in a diocese and of course, through him, with the Bishop of Rome, the Pope.

I remember on one occasion visiting a group of young people who were preparing for their Confirmation.  During the visit, I asked one of the boys why he had chosen Saint Patrick as his special Confirmation patron Saint.  He told me that it was because St Patrick had driven all the snakes out of Ireland – the young man concerned was very impressed by this feat - and also because St Patrick had used a three-leafed shamrock to explain the mystery of the Trinity.

His answer reminded me that I too had learnt about St Patrick and the shamrock when I was a little boy.  Whenever the nuns wanted to talk about this mystery of our faith, they would use the shamrock – three leaves but only one plant – and also the example of the triangle – three corners but only one shape – to explain how God could be three persons and still just the One God all at the same time.

When I was young this was really all that the Trinity meant to me: it was an interesting mathematical problem.  How could one be three and three one?

As I have grown older I certainly haven’t arrived at a full understanding of this mystery.  At least from one point of view it doesn’t seem to make sense in terms of our understanding of how the world works.  What I have come to understand however is that rather than try to solve the problem of the Trinity, as Christians we are actually being invited by the Lord to immerse ourselves in the mystery.  We don’t have to work out how God can be one and three at the same time.  What we are asked to do is allow ourselves to be drawn into the truth about God which we could never have discovered for ourselves but which reveals to us something of the beauty and wonder of God’s life.

At the very heart of the mystery of the Trinity, of course, is the realization that God is not isolated and alone but is, in fact, in some mysterious way, a communion of life and love.  We have been taught by the Scriptures to speak of God as Father, Son and Holy Spirit, and these names all point to the idea of relationships.  After all fathers need children in order to be fathers and children need parents in order to be their children.  God has taught us, in the Scriptures, to speak of him and to him as Father, Son and Spirit, because God wants us to see that the very meaning of life, of existence, is relationship and dependence.  God is the source of everything that exists and our faith teaches us the in some mysterious way everything that exists reveals something of the mystery of God.  And this is especially true of us as human beings, created in God's image.  What our belief in the Trinity is teaching us is that it is in their relationships of love and self-giving to each other, their unbreakable and intimate communion with each other, that the Father, Son and Spirit are the one God.  And of course, because within the Trinity God is all about self-giving, this self-giving love of God flows over from God himself into our world and into our lives. We live, and the whole universe exists, because God is a God of love and self-giving. We are the creation of God’s love.

What does this mean for us?  I think it means everything for us. In the first book of Genesis, in the creation stories which we know so well, we discover that God has created human beings in the divine image and likeness.  When the author of those words wrote them down, he couldn’t have known the depth that was contained within them.  For the Jewish people God is one, as he is for Muslims and as he is for us.  But no other religion has ever understood that this one God is a communion of love.  The world had to wait for Jesus for this to be made known.  And if we are created in the image of God, then we are created in the image of a communion of love.  This means that our vocation, our God-given destiny, can only be fulfilled to the extent that we live in relationships of love and self-giving, just as God lives in a relationship of mutual love and self-giving between the Father, the Son and the Holy Spirit.  “God is love” says St John “and the person who lives in love lives in God.”

On this Feast of the Holy Trinity God is calling us to be his living images in the world by living our lives in relationships of love, mutual support and self-giving.  It is an invitation to all of us: to husbands and wives, to parents and children, to brothers and sisters, to friends, to parishioners – to all of us.

If we open ourselves to the gift of God’s Holy Spirit, we will find ourselves drawn into an intimate communion with Jesus, who will lead us to the Father.  This is the way for us to live the high ideal which our human and Christian vocation puts before us: to be the living images of the God of love in our world today.