Recently, Christians across the globe have celebrated Pentecost, the feast of God the Disturber – the holy mystery who heals and provokes, who unleashes tongues of fire against cosy religion, who threatens our institutions and breathes new possibility into our lives. Great stuff. Except that for the most part, if we’re honest, many of us find actual 'charismatics' a bit uncouth or unhinged. And by the same token, while we’re all in favour of change, we fervently hope it doesn’t make too much difference. Not to us, anyway. But those folks down the road look like they need a shake-up.
The point is, the Spirit that blows where it chooses (John 3. 8) sits ill with security and good order. Perhaps that’s why, after almost ten centuries of umming and ahing, the church in its wisdom finally decided to follow the divine anarchy of Pentecost with the only Sunday in the Western Christian liturgical calendar dedicated explicitly to a suitably daunting doctrinal theme – the nature of God.
Trinity Sunday (3 June 2007 ) has long been known as a graveyard slot for preachers, who find themselves tied up in theological knots, wondering whether there’s any hope of escape. Much the same thought probably passes through the mind of their congregations, too, other than in those churches for whom Christian believing is a matter of simple assertion rather than demanding explanation.
This confusion and nervousness about what is, after all, the central Christian confession, is compounded these days by the fact that a great many people, including a number who sit in church pews, have decided that, whatever spiritual benefit the Christian faith may offer, its chief glory does not reside in the historic Trinitarian formulas, which seem unrelated to much Scripture (they feature only by contested implication in the later parts of the New Testament) and pretty incomprehensible to the modern, rational mind.
This is a shame, to put it mildly. Because if the core of our faith is nonsense, might we not just as well pack up and go home, or at least try to come up with something more adequate to our contemporary sensibilities? For what is at stake in the Trinitarian question is the very credibility and power of the One to whom Christians are supposed to testify. If we are serious about why we are part of the church, other than just to be comforted or entertained, the challenge doesn’t get any bigger than this. 
Like many Christians, I confess that I have sometimes come close to irresolvable despair in considering how to make sense of what the tradition has to say about God. But that is not where I find myself now. I am much more positive, and I owe my renewed sense of hope to the continual provocations of those who, on the one hand, will not let Christianity slump into 'mere dogma', and who on the other hand resist falling prey to the illusion that what the Gospel says about life in its fullness is basically what any right-thinking person could dream up with a little common sense and less of this messy God stuff. (That appears to be where someone like Bishop John Shelby Spong has ended up. I admire his forthrightness, but I believe he seriously underestimates the subtlety and suasion of the traditions he thinks need sweeping aside.)
On the contrary, I want to argue that ‘the God stuff’ is absolutely vital, and that far from being an intellectual liability, Trinitarian speech patterns are actually essential to figuring out how we can go on attending to God at all in the ordinary world – especially in an age where people have lost touch with Christian modes of thought, so that the radically new possibilities the Gospel offers us (repentance, forgiveness, self-giving love, peace and restored life) are in danger of shrinking to little more than another brand of self-help therapy from the big, bad world’s ‘religious supermarket’.
To put it another way, going on with the business of believing in God (or else facing the consequences of not being able to do so) is essential, because the alternative is either to embrace despair or to delude ourselves that somehow we can become perfectly well-practiced in the art of forgiveness, say, without needing to draw on the unconditioned divine life which – so the Gospel awkwardly claims – alone enables us to move beyond personal egotism and positional arrogance. (Richard Dawkins is far from alone these days in believing that all religion is 'delusional'. But what really is delusional is the idea that we can create a better world without being better people, or become better people without having our lives transformed by a love which is truly beyond bargaining or manipulation – because it belongs neither to us nor to anyone else, but is pure gift. God’s love, that is, since there is no other kind of love that can possibly make that claim - derived from the fact that, unlike us, God has no need to compete for space, validation, status or attention in the world.)
It is this endless ‘givingness’ of divine life to which the Trinity points. Put in the simplest terms, what the doctrine says is this. The life of God is the origin and destiny of the whole universe (as the Trinity Sunday readings from the Psalms and the Book of Proverbs make plain). But that alone is not enough – otherwise we might conclude that God is remote, and that talk of divine love is mere unanchored romance. So God is also the kind of transforming life we see in Jesus – a particular person whose humanity is utterly transparent to that unconditioned love which is God’s alone; a divine love which does not cancel out human life (as if the more there is of God, the less there has to be of us, and vice versa). Rather, in what we come to call the incarnation, the liveliness of God fulfils and deepens human potentiality, even in the face of death.
This only makes sense, incidentally, if the power, presence and personality of Jesus is deeply rooted in God’s transcendence. Simply positing Jesus as "the nicest guy ever" just doesn’t hack it, because we couldn’t ever know he was, and because this trades on the fantasy that a really, really good human is a bit like God – which assumes we know already know what 'Godness' is, such that we can fit it into our scheme of things. Whereas the whole point is, we don't and can't. God is utter mystery known only in self-disclosure mediated by what we are able to grasp - the world of people and events.
Trinitarian Christian speech, by contrast, turns out to be much more rational and realistic - by working the other way round. It suggests not that God is straightforwardly ‘like’ Jesus or vice versa, but that when we develop a relationship to Jesus’ life we meet in that life (and not in some esoteric, flesh-free 'spititualised space') a decisively truthful glimpse, though not the totality, of God’s intentions towards us – something even the judicial murder of crucifixion cannot eliminate, because all this is God’s doing, not unaided humanity’s.
So, we begin to learn that the God who is the mystery of the world is also the mystery of humanity in Jesus. But that also is not enough, because not all humanity is instantly connected to Jesus and not all life is human. So God is also given as Holy Spirit, as the transformative possibility of God between human beings, between us and creation (that is, the world understood as called towards love), and between us and the God who comes to us in Jesus.
God, in other words, is now and forever the transcendent mystery of the world, the 'Word' (or reason) of God expressed through flesh, and the energy of God continually inviting us into the ritual of life and equipping us to dance. As Nicholas Lash  puts it, what we are talking about here is three irreducible and mutually interdependent ways of believing in one God – belief, in this case, residing not in a proposition, but in experimental living. How do we touch God’s creativity? By developing and celebrating each others’ creativity. How do we touch God’s love for humanity? By refusing all that imprisons human beings in themselves. And how do we touch God’s spiritedness? By nurturing the everyday gifts of the Spirit – not abstract or 'religious' virtues, but love, joy, peace, patience, kindness, goodness, faithfulness, gentleness and self-control (Galatians 5.22). This happens personally and corporately.
Put this way, I hope you can at least begin to see that 'Trinitarian language' is about several very important things. First, holding together elements of God’s life which superficially appear in contradiction (transcendence and embodiment, say) and which we would otherwise be tempted to separate, to turn into a hierarchy or to ignore. Second, discovering the nature of God by learning to re-order our lives according to the promise of God’s endlessly hidden appearances beyond, in and between us. Third, constantly repeating (in speech, sacrament, song, deed and thought) the figurative grammar which goes on linking us to the modes of God’s life and God’s modes of living to us. In this way we "become Christians".
The chief difficulty we have with all of this, I suspect, apart from the fact that it demands our lives not merely our assent, is that the components that make up this all-embracing 'traditional' Christian speech about God have come to us in abstract Greek metaphysical categories - ones which address questions and formulate responses that seem remote from our habits of thinking. Our task, then, is to so inhabit what our predecessors were trying to say that, discovering its fruitfulness, we can say "if they put it like that then, how would we put it in our language today?" This is what I am trying to do here, but in re-connecting with our inherited Christian language we also find we have some clearing to do to get to the place where it all begins to make more and more sense.
For example, I once heard a well-known theologian wrily observe that grasping Trinitarian language is not too difficult... once you realize that ‘one’ and ‘three’ aren’t numbers in a sequence (but rather ways of speaking of a singularity embracing beyond the merely numerical); that ‘persons’ in the Trinity are not human persons (the Greek means something like dramaturgical ‘masks’ or ‘appearances’, and was deliberately chosen to avoid what we now denote by ‘personalness’); and that ‘substance’ applied to God doesn’t mean ‘stuff’ (but true essence beyond our knowledge of ‘thingness’)!
In other words, Trinitarian doctrine is not trying to describe God as you would a person or an object. But nor is it simply a mirror held up to our nice ideas about God. Instead it refers to what we can know by participation, rather than 'forensic examination' or speculation, about the life and affection of God encountered through the excess of the world, the unrestrained humanity of Jesus, the limitless donation of the Spirit, and the outstretched community of the church. It is therefore about image and relation, not some silly empirical claim to see into the very core of God when, frankly, most of us couldn’t claim to have much of a clue about what makes our spouse or neighbour’s cat tick – let alone the giver of the universe!
All of which brings us to that remarkable and famous icon about the Trinity  painted around 1410 by Andrei Rublev. If we are swimming intellectually, this image will, I hope, begin to make what is being said more approachable. First, let’s be clear, this isn’t (as the untrained modern eye might assume), a representation of ‘God in three figures’ - a sort of celestial tea-party. Absolutely not. An icon is something to look through, not at. You need to go beyond the immediate appearance to ‘see’ what is ‘hidden within and beyond it’, so to speak. In this case, the three gold-winged figures are the visitors encountered by Abraham as he camps by the oak of Mamre. As he talks with them he finds himself mysteriously in conversation with God through being drawn into their curious communion, symbolized by the chalice. This only works if the picture, like the doctrine, is figurative – the opposite of what our modern minds fear, thank God, which is naive ‘literalness’.
The life of God is seen by looking at what is happening between these figures, not by objectifying them or substituting one or more of them for God. In particular, as Rowan Williams has pointed out, God’s life is envisioned (rather than pinned-down) in the mutual, non-competitive and continual loving gaze of each toward the face of the other, creating a perfectly free unity of relations – rather than a homogeneity of ‘things’ or ‘stuff’. To appreciate this is to receive divinity as beauty in prayer, and to find in that beauty a loving dependence on the indwelling, expanding love of God. Such a tiny glimpse of divine possibility is then strengthened by living, serving and praying together – seeking to see and respond to more of what God goes on giving as we enter a shared life-journey of transformation.
This, then, is the 'Trinitarian' task of the church, according to St Paul in Romans. Not to create abstract formulas about God, but to allow the language that flows from Christian encounter with God to remind and teach us so to live, labour and long that the Creator who brings life to the world, the Christ who brings peace and the Spirit who brings love may be understood more and more as the true source and goal of our flourishing. As Jesus declares in John 15. 26-27: “The Advocate…, the Spirit of truth who comes from the Father, will testify on my behalf. You also are to testify because you have been with me from the beginning” (John 16. 12-15).
This leads to two final remarks. Jesus calls God Father. And in Matthew’s Gospel (23.9) he tells us to call no-one else on earth ‘father’, not even our biological fathers. In Jesus’ day, we need to understand, fatherhood alone was seen as being able to donate the seed of life. These days that biological assumption is not sustainable, but that’s what it means in the symbolic, participative language of the New Testament. As several women scholars point out, by removing ‘fatherhood’ (loving generativity) from the exclusive preserve and control of men, and preserving it in God alone, it is transformed, and so invites us to transformation beyond the limits of biology and culture - including an adoption of the variety of gendered and non-gendered images of God made available to us in the Bible and after.
A similar transfiguration takes place with the Spirit’s falling upon all kinds of foreigners and weirdos at Pentecost and elsewhere - from which we deduce that the God who is spoken of as Trinity is not restricted to Christian propriety, just as Jesus did not build a church but a Beatitude community, and the Fatherliness of God is universal before it is particular (as the prologue to St John makes plain).
In Trinitarian Christianity, then, we have a unique language which holds plurality to be integral to God’s universal purpose, expressed in the particularity of Jesus and multiplied as life in the Spirit. The Christian hope in seeking God's realm and will is that those who taste this abundant, divine life will be strengthened to develop and share it as widely as possible. For “We have peace with God through our Lord Jesus Christ…We rejoice in the hope of the glory of God… And hope does not disappoint us, because God’s love is poured out into our hearts by the Holy Spirit.” (Romans 5. 1a, 2b and 5a)
 Adapted from a sermon preached at St Mary Arches, Central Parish of Exeter , on 3 June 2007. Texts: Proverbs 8:1-4, 22-31; Psalm 8; Romans 5:1-5; John 16:12-15.
 A correspondent, David Ardagh-Walter, asked me for a really simple summary. I think I'd say "God ahead of us, God for us, and God between us", developing a catechetical phrase attributed to St Basil the Great... but trying not to get caught in what is now the metaphysical trap of 'before', 'beyond' and 'within'.
 See also: What difference does God make today?