The fourth person of the Trinity?

And so on Trinity Sunday we reflect on the godhead of the Christian faith, alternatively the mathematical impossibilities of three in one and one in three.  That which few understand and fewer share, yet the part which is present in pretty much every liturgy – God: Father, Son and Spirit as if rising from the dead and vanishing into the clouds wasn’t enough we complicate the story even further.  So much so that theologians have argued over the exact composition for centuries. That all might be true, but I’m not sure it should be.  Despite the complicated ideas bounded around the trinity should be one of the simplest ideas to express.  The idea of the trinity allows a creativity, one which is expressed beautifully in the image prayerfully painted by Andrei Rublev.  The three persons of the ‘old testament trinity’ or ‘hospitality of Abraham’ as Abraham and Sarah entertain angels under the oaks of Mamre.  Only the three angels find their way onto the canvas – more for the theologians to muse and argue over which character is which – or perhaps it doesn’t matter, perhaps actually for once working out what is going on is not the point at all.  These icons are to be meditated on not thought about and this one in particular as it is perhaps the best of its age.
Just to complicate matters even further, i’d like to suggest that there are four in this trinity – I know, we’re back to the mathematical impossibilities again, but bear with me.  The trinity icon draws you into it, probably due to the clever use of lines of perspective, but never mind the technicalities from the 15thC.  However it happens we are drawn in to the table and become ourselves the fourth person of the trinity.  It is an invitation to move from isolation to community.  An invitation to join the dance as it were.  To sit at table in the midst of all that is known and understood, and all that is unknown and to be discovered about God.  This is our invitation and it is so very simple.  God acts and works in community, and we are a part of that action if we accept the seat at the table. To accept the seat is to be part of God in community Holy and One.