I hope you’ll forgive me if I eschew the customary Trinity Sunday joke about celestial mathematics. It’s usually made in a rather apologetic fashion to give the impression that the preacher isn’t too bothered about all this high-flown doctrine, and is much more interested in more practical things, like being nice to old ladies. Even some of my fellow ordinands dread the prospect of having to preach on Trinity Sunday. They see it as a dry, doctrinal affair compared with the preceding drama of Eastertide. And to some extent, they are right: this is the odd one out among the feasts of the Church, in that it is the only one which is based not on an event or a person, but on a doctrine. As such, it is condemned for one of the greatest sins of modernity: not being ‘relevant.’

‘Relevant’ to what, though? – the question we should ask whenever the well-meaning trot out this overused and underdefined word. Generally, they mean ‘relevant’ to the man on the Clapham Omnibus, with his workaday concerns. Personally, I find this approach rather patronising, not least because the man on the Clapham Omnibus is far more likely today to be a black or Asian woman, who may have a far keener interest in her religion than the stereotypical overall-clad Englishman of yore. What I hope to show is that the doctrine of the Trinity is ‘relevant,’ not just to the pallid ranks of theologians in their sun-starved ivory towers, but to the great diversity of people who make up the body of our Christian Church.

After the heady events of Our Lord’s Crucufixion, Resurrection, Ascension and the sending of the Holy Spirit upon His Church, Trinity Sunday gives us a much-needed chance for reflection: what does all this mean? And certainly, this must have been the first question the disciples of Christ asked themselves after Pentecost. Some twenty years later, we see St Paul wrestling in his letters to conceptualise the mystery of Christ. God the Father sends His Word to earth, His Wisdom that existed before all Creation, and this man Jesus speaks in ways that clearly identify Him with God. His Ascension confirms his unity with the one he calls Father, such that we detect in St Paul a sort of ‘Binitarianism’: not as an abstract doctrine, but a way of coming to terms with the apparent contradiction that Jesus is both man and God. It is all there in the earliest parts of the New Testament, and indicates the conceptual struggle going on earlier still within the church communities. And here, too, in the letters of St Paul, we find the baptismal blessing in the name of the Father, the Son and the Holy Spirit; and while this does not show that a doctrine of the Trinity had been established, it does at least reveal how closely, even to the earliest Christians, the Spirit was linked to the work of God the Father and the Son.

Without this time for reflection, for wrestling with the questions that would later become doctrine, the events of Eastertide would make no sense. But over time, some sort of sense was reached. Now, the doctrine of the Trinity is not clear, not a precise work of mathematics: but given the organic way in which the doctrine developed, in response to the strange, inexplicable events that the Apostles had been through, this should not surprise us too much. They had spent their lives following a man who claimed to be the Son of God; they had seen Him die and rise again; they had watched Him ascend to the heavens; and then, the Spirit that He had promised them swept through them like fire and stayed with them to do His work. How else could they see this, but as the same Word of God that existed before time, the same Word of God Incarnate in the man Jesus, the same Word of God filling and animating Christ’s body of earth in the new incarnation of His Church? If Jesus Christ was not God, then all we have is a dead Messiah; if the Spirit that animates us now is not the Spirit of Christ, then His promise to be with us forever was a lie, and we have no hope. The Trinity is the deepest expression of our struggle to know God, the best we can do to come to terms with the strange story that makes our faith.

But despite the conciliar formulations that would three hundred years later define it more clearly, a struggle it remains. No defintion has ever been fully satisfactory, not even the Athanasian doctrine that we hold orthodox. And perhaps, may I venture, this is quite proper: because to quote the Dionysius, ‘if you understand it, it is not God.’ When the Jew or the Muslim affirms that ‘God is One,’ the Christian can agree- but only to the extent that God is also three. And I think this a significant caveat. For if we make God simply ‘one,’ then He becomes comprehensible by a human, mathematical concept. Or then, if we worshipped three gods, we would likewise reduce the divine to a formula that we can understand. But when we say that God is One and God is Three, we remove Him from the realm of normal human logic, and we show that His being as Father, Son and Holy Spirit, whatever our doctrinal quibbles, remains firmly beyond our grasp.

But the Trinity is not just a matter of showing what God is not. It also makes a positive statement about the nature of the divine, a statement that shows the very heart of Christian belief about God. And this is why it is so important to our woman on the Number 173, or whatever bus goes through Clapham these days, and to all the rest of us. In the Trinity, God reveals Himself not just as a homogenous, static unity, a great, monolithic force set in absolute opposition to everything else. Rather, the Triune God is dynamic, differentiated, even communal in its very nature. Ultimately, God is Trinity, because God is love. The love of the Parent for the Child and the Child for the Parent, the love of the Child for us as Siblings, the love of the Parent for us as Children, and all this bound together in the relationship of the Divine Spirit which flows throughout all in heaven and all on earth. God could not be love if He were alone. No, the lover must love another: and so our God is Other not just to us, but even to Himself, in the deepest essence of his nature. The Trinity is important, then, because it shows how within God’s unity, there must be diversity; and so, within the single body of His Church, if we are to love one another, we must have others, different from ourselves, to love.

So if this does not conform to our mathematical expectations, too bad. As I say, the Trinity is not a dry doctrine composed for the amusement of theologians: it is, rather, the real struggle to understand how Jesus can be human and divine; and at the same time, in its messiness and contradiction, it shows us the limits to our understanding of the unknowable depth of God’s love.

The opinions represented herein are those of Thomas Plant only.