“To put it another way, God’s unity is ontological and not just ethical. God’s unity is not the result of a harmonious unanimous vote within the Godhead. The three persons do not form a committee. God’s unity just is the complete and whole interpenetration of the three persons of Father, Son, and Spirit.”
Some years ago, J. Ligon Duncan, chancellor of Reformed Theological Seminary, declared in a sermon at the historic First Presbyterian Church of Jackson, MS that God was “not an undifferentiated monad!” Precisely so. The God of Scripture is Triune: Father, Son, and Holy Spirit. He is a Triunity. God did not create out of loneliness, as if he needed the company. God is an eternal being of communal fellowship within himself. One error we want to avoid, though, is thinking of God’s unity as something other than the three persons of the Godhead in their perichoretic unity.
To put it another way, God’s unity is ontological and not just ethical. God’s unity is not the result of a harmonious unanimous vote within the Godhead. The three persons do not form a committee. God’s unity just is the complete and whole interpenetration of the three persons of Father, Son, and Spirit. The essence is not some fourth substance that hides behind three drama masks. And yet, God is thoroughly one as well as three. The persons, let it be said, are ontological too since the essence is not something other than the three persons.
I have used the technical adjective “perichoretic” which is derived from the Greek word perichoresis. Some of my readers may be familiar with its Latin forms circumcessio or circumincessio. These terms refer to the divine reality of the mutual interpenetration of the persons of the Triune Godhead. The Father is not one part of God, and the Son another, and the Spirit a third as if they were so many slices of pizza. The Father is all God, the Son is all God, and the Spirit is all God and yet there is only one God and not three. Perhaps some of you have seen an attempt to capture the nature of God with the use of the illustration of three overlapping circles (much like a Venn diagram or the Olympic game’s logo). As with most if not all such illustrations drawn from human experience, we wander into theological error with such a chart. Three overlapping circles suggest that there is a part of God that is not the Father, a part that is not the Son, and a part that is not the Spirit. This is plainly wrong.
The Father is not one third of God, the Son another third, and the Spirit a final third. Remember the doctrine of divine simplicity? God is not made up of parts more basic than he is himself. To illustrate, a brick wall is made of several bricks and mortar and these are the basic building blocks of the wall. God has no basic building blocks. The Father is not more basic than the whole Godhead, nor is the Son, or the Spirit. If you find this all rather mind-blowing, you should. If you find this boring, or abstract, or a yawn, you fail to understand your God. Perhaps, as J. B. Phillips said long ago, “your God is too small.”