To exist in God is to exist in trinitarian relationships with the world.

The liturgical calendar calls this Sunday "Trinity Sunday" a day set aside to "celebrate" the unique triune character of our God: Father, Son and Holy Spirit.

"Celebrate" or stumble over? The complex theological doctrine of the Trinity has always managed to leave scholars somewhat frustrated and the faithful somewhat confused. Trying adequately to express the mystery of a God who is Three-in-One tends to leave us tongue-tied.

Symbols for the Trinity include a circle inscribed within an equilateral triangle. Actually, during the first eight centuries of Christian art, the image of the triangle for the Trinity was not widespread although on one of the gravestones in the catacombs there is a triangle in which the …