I'll see you on the dark side of the Triune
This article is an edited version of a sermon delivered by The Rev'd George Pitcher at St Bride's on Trinity Sunday, 3rd June, 2007

The Trinity and Mystic Pietà Baldung Grien, 1512
It's an axiom of those of us who have to preach that if you think you understand the Trinity, you cease to. It's said that an inquiring woman once asked the great American Roman Catholic theologian Archbishop Fulton Sheen to explain the Trinity to her. After a brief, five-minute discussion, the woman thanked him and began to rise. She said: "Great. Now I understand the Trinity completely." He grabbed her by the arm and asked her to sit back down, saying: "My dear lady, if you think you understand the Trinity completely, I haven't done a very good job."
It's in the nature of Trinitarian theology for it not to be understood. It is a mystery. So it's meant to be beyond us. Augustine and Aquinas admitted as much. But that doesn't stop theologians trying to explain it. I've heard it said that the Trinity is like water, steam and ice - the same thing, just in different states. But God in different forms is called Modulism, and that's a heresy according to the hardliners, as if we care.
The orthodox view holds that there are three divine and separate entities that make a unified whole, like notes that make a chord. A unity that's worth infinitely more than the sum of its parts. Three in One and One in Three - like muskateers with a can of oil.
But I'm not sure that gets us any nearer to anything that actually explains how a Trinitarian God works. If the Trinity is to mean anything to us, it should go some way to explaining what God is like. Otherwise it's just a theological notion - interesting for some dons to argue over at their universities and of no practical use to the rest of us.
I do think the Trinity has a practical purpose in explaining the nature of God. Whether it was the intention or not of the early church fathers, the Trinity is potentially highly revealing of the nature of God, as Christians understand it, if it is treated as metaphor. Paradoxically, so much of the Christian faith becomes practical and real as soon as it is treated metaphorically, rather than literally. The literalists would never have converted me - and I assume I'm no great loss to them.
Let me explain a process that I went through while I thought about what to write about the Trinity. Later this year, I've been asked to preach at my daughter's college chapel at Cambridge. This is somewhat daunting - the Dean is a theologian of some standing. So I thought I should start preparing early. On the college website, I clicked on "Chapel" to case the joint. I soon found that some of the better sermons are available as a download (so not a little pressure to appear there). And I saw that a good friend, Susie Snyder, who was ordained alongside me, preached there last year (it's actually her old college, so not a little more pressure for her).
I listened to her sermon. It was about asylum seekers and our willingness or resistance to embrace them in our midst. She referred to biblical injunctions about how we should welcome the alien, the stranger. And she referred to our suspicions of "the other", which she put in the psychological context of our dark side, our alter ego, the side of us that shames us. Her point was that aggression towards the outsider is often the result of us displacing our repression of the other, darker person within us onto someone else.

Pulitzer Prize winning author, Jack Miles
Leave aside the person of the Holy Spirit, the great enabler, God's agent, the one who gives us strength and inspiration for whatever "tribulations" are thrown at us. Leave that Holy Ghost aside for a moment. If the ministry of Jesus of Nazareth and the Risen Christ is God dirtying himself in the mire of human affairs it has the profoundest implications for our understanding of the darkness of our world - what we call theodicy. Because if God has made darkness and pain and hatred an aspect of his own life, invested in the experience of Christ and absorbed into what we call the Trinity, then there is nothing in this world that is beyond God's reach and nothing that can't be transformed through the love of the Christ.
We, who are asylum-seekers, are bound to ask "why?" when evidence of great loss, pain, sin and death enter our lives or those of the ones we love or even those of strangers in newspapers. The lives, very often, of those "others". When cancer strikes, when families are atomised, when we grieve for the lost and kidnapped, when a child is taken in the night, our faith is naturally shaken - and it should be. What is God up to? Where is God? Is God there? The answers to those questions, pathetically, must remain mysteries. Pathetically, because I don't pretend that it's a comfort in this world for the oppressed, the dispossessed, the violated and the desperate to be offered a God who shares their misery. Why would they care? This sure as Hell isn't Heaven. But one thing that Trinity Sunday tells us is that God has apparently chosen, triangulated in Christ, not just to embrace our dark side, but to make it his own.