So - yesterday was Trinity Sunday. It's the only major festival in the Church's year that doesn't relate to an event. Instead it's pure theology - a chance to re-examine our understanding of God.
The early Church soon realised that the Jesus-event required a radically revised picture of God. It then took them a few hundred years to finalise the doctrine of the Trinity. One God in three persons - how does that work?
Well, what the Trinity doesn't do is give us an exact, definitive, final understanding of God. Actually, nothing can do that. The moment someone claims to have understood God fully, please feel free to call them a delusional fool. You have my permission (for what it's worth). Remember Moses, asking God politely what his name is (knowing it will be easier to sell the whole Exodus thing to his fellow-Israelites if they can pin a name on their God, and thereby define him). The answer is (depending on how you take the obscure Hebrew phrase) "I am who I am" or "I will be who I will be". In other words, mind your mortal business, Moses. I AM is not a God to be put in a box, measured or controlled. Arguably, this God is better understood as a verb than as a noun. After all, nouns - people, objects, places - can be safely located and objectified. This God isn't an object - more like a process.
Anyway, after that little excursion ... the point is, the Trinity is the Church's best shot at a picture of God that doesn't mislead us, and equally important, doesn't miss out anything vital. Leave out the Father, the Creator, and there is nothing, literally nothing, to talk about. Leave out the Son, and you miss that critical self-revelation of God in Jesus Christ which gave birth to the whole meaning and purpose of the Church. Leave out the Holy Spirit - God present and active in us and around us - and you're doing no more than worship the past. We need all three. And yet, the wonder is that they are one, they are united in love; and that love is not simply shared among the Trinity, but endlessly poured out on all God's people. On all of us, if we can only notice it, feel it, open ourselves to it.
I did say there'd be some theology. Of course, words can't capture God. But words can still be accurate (as far as we can tell) and helpful - or not. So we carry on praising our wonderfully mysterious God, the Trinity. These words from the book of Ecclesiasticus say it well: "We could say more, but could never say enough; let the final word be: "He is the all"."