Last Sunday, June 4, we celebrated the feast of the Holy Trinity, one of the most profound mysteries of the Christian faith, the nature of God as Father, Son, and Spirit. The doctrine of the Trinity sums up the Christian understanding of the mystery of God. “It is impossible to believe explicitly in the mystery of Christ,” Thomas Aquinas wrote, “without faith in the Trinity, for the mystery of Christ includes that the Son of God took flesh, that He renewed the world through the grace of the Holy Spirit, and, again, that He was conceived by the Holy Spirit” (Summa Theologica II-II, q.2, a. 8).
Christian theology is made possible by the self-communication of God the Father in the Word-made flesh and our apprehension of God-in-Christ occurs only because we have been drawn by the Holy Spirit who dwells within our hearts and elevates our whole consciousness.
In contemplating the Trinity, we see a perfect unity of persons, each person of the Trinity is distinct, yet they exist in an eternal, inseparable relationship. Trinity Sunday is not a distant theological abstraction but rather a graced opportunity to reflect on the mystery of God as a family of divine persons who invite us into their community of love, grace, and peace.
The divine communion of love is a model for our own relationships as the people of God. We are called to love one another, to live in harmony, and to see unity amidst our differences. This should happen not just at the level of our own family and friends but at the wider parish and community level as well.
Unfolding in Time
In the Old Testament, there was no real awareness of the Holy Trinity. For the Jews, God was one person, Yahweh, and that is how they understood and related to him. This period in our salvation history is sometimes referred to as the era of God the Father.
With Christ’s coming among us, we were given a deeper insight into the reality of God. Jesus frequently spoke of the close relationship between himself and his Father. He prayed to the Father, but he also said that he and the Father were one. This period when Jesus was physically present among us is sometimes described as the era of God the Son.
Jesus also spoke of the Holy Spirit and promised he would send the Spirit to be with us. When, after his Ascension into Heaven he fulfilled his promise, the full story of God’s inner life was revealed: God is one and God is three, a triune God. Today, you could say we are living in the era of the Holy Spirit, who is the presence of God among us until the Lord’s coming at the end of time.
Completion of Love
If God were one person, then God would find infinite happiness in glorious isolation, all alone, loving himself. And since we are made in the image of God, we too would find our happiness in turning in on ourselves, loving ourselves, and being alone. But God’s happiness consists in the love that the Father has for the Son and the love that the Son has for the Father. And the fruit of their love for each other is the Holy Spirit. God is three persons united together in love.
So, when Jesus speaks about the love the Father has for him and his love for the Father, he is talking of a mutual love which is the Holy Spirit.
But even the love of the Three Persons for each other was not sufficient for God to be infinitely happy. God created us human beings and wrapped us up in God’s gratuitous and unconditional love, because the happiness of the Father, Son, and Holy Spirit only finds its completion in their love for each one of us, and so our happiness, too, can only be found in loving one another and God.
A Life Lived in GodAlthough there are three persons, there is only one divine nature or essence. Because of the unity of essence, there is a mutual indwelling of the Persons, of one in the other.
At the beginning of every Mass, we are welcomed with this Trinitarian greeting of St Paul, “The grace of the Lord Jesus Christ and the love of God and the fellowship of the Holy Spirit be with all of you.” The goal of the Christian life is to grow each day in loving communion with the triune God. To believe that God is a trinity of divine persons is to receive God’s merciful invitation to daily friendship with the Father, through the Son, in the power of the Holy Spirit.
The mystery of the Trinity invites us to delve deeper into our faith. A life lived in God is a life that creates out love like the Father, reconciles like the Son, and inspires like the Holy Spirit.
Written by Marie – Therese Cryan