Trinity
God is three and God is one: He is not eternal loneliness, but eternal love. This love unites the three Persons of the Trinity, and is the cause of all that has life and existence. The unity brought about through this love – the trinitarian unity – is a higher form of unity than that created by separate but indivisible building blocks. The highest form of unity is not one held together like a straightjacket – this kind of unity is held together by love.
KNA
A depiction of the Mystery of the Trinity. Icon by Andrei Rublev, 1412.
André Roublev's famous fifteenth-century icon of the Trinity is one of the most beautiful depictions of this mystery. The icon does not attempt to paint a picture of God as he is in himself – who would dare to do such a thing? Rather Roublev shows us the Trinity by holding up a mirror. In the mirror we see depicted an historical encounter: the three men visiting Abraham by the oakes of Mamre (Gen. 18:1-33). Abraham quickly grasps that these men paying him a visit are no ordinary men; he experiences a visit from God through these three men. Already there in the text of the Old Testament is it clear that the number three is mystically expressive of the unity of God: A Trinity is the object of the adoration of the One.
The story of this visit of the three men to Abraham was understood by Christians early on as a mirror in which one could catch a glimpse of the Trinity. Roublev's icon makes the event visible to our eyes, at the same time as its mystery is preserved. I would simply like to draw attention to one of the aspects of this rich icon: the setting of the event, which is expressive of the mystery of these persons. Firstly, we have the oakes of Mamre, which Roublev reduces to one single tree, which here becomes the Tree of Life – the Tree of Life which consists simply of the Trinitarian love, which caused the world to come into existence, which keeps the world in existence, which redeems the world, and which is the source of all life.
Secondly, we have the tent, Abraham's home, which makes us think of John 1,14: “The Word was made flesh and pitched his tent amongst us...” The body of the Word Incarnate has itself become a tent, a home, where God dwells and also offers us a dwelling place with him. Finally, Abraham's offering, “curds and milk and the calf”, is replaced by Roublev by the chalice, symbolising the Eucharist in which God gives himself. […] The tree – the tent – the chalice: They tell us of the mystery of God, and at the same time they reveal to us his innermost being: trinitarian love.
Homily given on Trinity Sunday, 6 June 2004, in Bayeux, France, in: Values in a Time of Upheaval, Ignatius (San Francisco), 2006, pp.161-167 (this passage, pp. 163-164).