On Trinity Sunday, the Church celebrates perhaps the most mysterious aspect of our faith: the Holy Trinity. Mysterious because the nature of the Holy Trinity — that God exists as three persons in one, Father, Son and Holy Spirit — is both a paradox and a glory.
The Trinity is complex and often misunderstood. The idea that God is three and one, both individual and together, emerged from the teachings of the early church, and still taxes many, great thinkers included. Perhaps that is how things should always be. Too much certainty can lead to arrogance, and not quite understanding the Holy Trinity reminds us that we do not fully know God. Our world is complex already, and the existence of the Holy Trinity both within the universe and beyond it is a marvellous example of how God is both within and beyond our understanding.
That said, why do we bother to try to grasp the Trinity at all, if it is so difficult?
Well, perhaps because it is a wonderful example of how God is with us, within us and beyond us in a permanent state of relationship. We talk a lot about relationships and fellowship in Christianity. We share, we love, we give and we receive: all impossible without relationships. The Holy Spirit, being three persons together, is purely and simply a relationship.
God the Father reminds us of our existence: we have been created by and through God. But God did not cease to care for us. We experienced Jesus as God the Son, who became human and died to redeem the world — another mystery, the resurrection reminds us of our fragile existence. Even then, with the hope and joy of the resurrection, God came again, to live among us as the Holy Spirit, the third person of the Trinity. And just as God the Father is with and in God the Son, so the Holy Spirit is with and in us, and we in and with the Holy Spirit.
God is present in all of us, and we are with God: the Holy Trinity is a mystery and a glory. We are united in God and therefore with each other. Trinity Sunday is a time when we celebrate relationships, our joining together and our capacity for love.