When did God reveal that there are three Persons in one?

THE MYSTERY OF THE BLESSED TRINITY AS REVEALED TO US
Proverbs 8:22–31; Romans 5:1–5; John 16:12–15

God’s revelation of Himself began gradually.  It began with Creation - its beauty and harmony are reflections of God’s wisdom and goodness.  Yet, because of the fall, humanity often misinterpreted creation, mistaking it for God.  Pagan religions worshipped stars, animals, or even humans.  God had to act more directly.

He chose a people -  Israel  - and revealed Himself to them as the one, true, living God: uncreated, eternal, and utterly beyond human comprehension.  This marked a profound development in human understanding of the divine.  Israel became the first nation to believe in one God, the Creator of all.

But that was only the beginning.

In the fullness of time, God sent His only Son into the world. The letter to the Hebrews tells us that, having spoken in fragmentary ways through the prophets, God now speaks fully in the person of His Son.  Jesus Christ is not only the messenger but the revelation Himself - the Word made flesh.  Through Him, we come to understand the deepest truth of God’s being: that the one God is a communion of three Persons - Father, Son, and Holy Spirit - equal in majesty, united in love.

This truth, so central to the Christian faith, is what distinguishes Christianity from Judaism and Islam, which still hold to the earlier and incomplete revelation of God's oneness without distinction of Persons.

Even though the fullness of divine revelation came in Jesus, the Church needed time - guided by the Holy Spirit - to unpack its full meaning.  The doctrine of the Trinity was not invented by the Church but discerned from Jesus’ own life and teaching. In today’s Gospel, Jesus speaks of the Father, the Spirit, and Himself.  Elsewhere, in Matthew’s Gospel, He commands the disciples to baptise in the name of the Father, and of the Son, and of the Holy Spirit.

The Spirit of Truth, given at Pentecost, has continued to guide the Church.  Through centuries of prayer, reflection, and debate - often amid heresies and misunderstandings - the Church was led to articulate the doctrine of the Trinity, which we profess each Sunday in the Creed.

We believe that the Son is begotten of the Father before all ages, the eternal Word through whom all things were made.  Today’s reading from Proverbs offers a poetic image of this: divine Wisdom at the side of the Creator, delighting in the world and in humanity - a foreshadowing of Christ.  This eternal Son took on human flesh and became one of us in Jesus of Nazareth.

We believe, too, in the Holy Spirit - the bond of love between the Father and the Son - who has been poured into our hearts, as St. Paul reminds us in Romans.  This Spirit makes us sharers in the divine life, the very love that flows within the Trinity.

So, the mystery of the Trinity is not a dry theological formula.  It is the very heart of our faith and the source of our Christian life.  In every sacrament - beginning with Baptism - we are drawn into the life of the Trinity.  The Spirit fills us with divine love so that we may love others with that same love, whether in our families, our parishes, or the wider world.

If we live by the power of the Holy Spirit - living lives of real, self-giving love - we will help draw the world into communion with the life of God.

Come, Holy Spirit, fill our hearts with Your love.  Make our homes, parishes, and communities places of unity and peace.  Give us wisdom to live each day in the light of the Trinity, and joy in knowing that we are called to share forever in Your divine life.  Amen.

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