Today is Trinity Sunday.  Years ago, the pastor of the parish to which I belonged, used to call this day “Heresy Sunday.”  He did not, of course, refer to today as “Heresy Sunday” because it is heresy to believe in the Trinity.  Indeed, the Trinity is the central mystery of our faith.  Rather, he called today “Heresy Sunday,” because the Trinity is such a mysterious reality about the inner life of God that it is very, very easy to lapse, even inadvertently, into heresy when discussing the subject.

We have to be very, very careful when we talk about the Trinity. 

Here’s an example.  Last year, I read in the newspaper that one of the Presbyterian branches was considering some new language to refer to the Trinity.  The traditional terms of Father, Son, and Holy Spirit were deemed to be too masculine, too gender exclusive.  So, these folks had hit on what they considered to be gender-neutral terms to describe the Trinity – Creator, Redeemer, and Sanctifier.  On the surface, I suppose that it makes some sense.  After all, it’s the Father who creates, the Son who redeems, and the Holy Spirit who sanctifies, right?  WRONG.

Fundamentally, the use of the language “Creator, Redeemer, and Sanctifier” to refer to the Trinity is, in effect, a denial of the Trinity.  It is an ancient heresy known as “modalism” or “Sabellianism.”  Modalism teaches that there is only one God, who reveals Himself as Father, Son, or Holy Spirit, depending upon what He is doing.  In Himself, modalists claim, God is not three persons.  At a given time, He functions in a mode: sometimes as the Father (who creates), other times as the Son (who redeems), and still other times as the Holy Spirit (who sanctifies).

Now, lest you think that mistakes like that are limited to Protestants, there was a Catholic parish in Australia that decided a number of years ago that, in order to be gender-neutral, their baptisms would be done in the name of the “Creator, Redeemer, and Sanctifier.”  And so they did, for a number of years.  All of those baptisms were subsequently ruled invalid – not really baptisms – precisely because they were not Trinitarian. 

But what is Trinitarian?  The traditional Trinitarian expression is one we all know: one God, three Persons.  There is a whole heck of a lot of meaning packed into those four words: one God, three Persons. 

The Catechism puts it like this: “The Trinity is One.  We do not confess three Gods, but one God in three persons, the ‘consubstantial Trinity.’  The divine persons do not share the one divinity among themselves but each of them is God whole and entire. ‘The Father is that which the Son is, the Son is that which the Father is, the Father and the Son that which the Holy Spirit is, i.e., by nature one God.” 

But, and here is the paradox: “The divine persons are really distinct from one another.  ‘God is one but not solitary.’ ‘Father,’ ‘Son,’ and ‘Holy Spirit’ are not simply names designating modalities of divine being, for they are really distinct from one another: ‘He is not the Father who is the Son, nor is the Son he who is the Father, nor is the Holy Spirit he who is the Father or the Son.’”

“The real distinction of the persons from one another resides solely in the relationships which relate them to one another.” 

In the orthodox understanding of the Trinity it is not the Father who creates, the Son who redeems, and the Holy Spirit who sanctifies.   In fact, all three of the Persons of the Trinity create; all three redeem; and all three sanctify. 

This is the theological principle known as the “ad extra axiom.”  It means that when God does something “ad extra,” to the outside of Himself, all three Persons do it.  The only exception is the Incarnation, in which only the Son took a human nature and united it to Himself.  We hear this axiom expressed poetically in our first reading, from the Book of Proverbs: “then was I beside him as his craftsman, and I was his delight day by day, playing before him all the while, playing on the surface of his earth; and I found delight in the human race.” 

Failing to uphold this axiom, which St. Augustine first expressed, inevitably leads one to a place where either you have one God (but not three persons) or you have three gods. 

“Father, Son, and Holy Spirit” really are the only way one can refer to the persons of the Trinity, precisely because they are words that uphold the relationships, the only distinction in God.

By this time, some of you (maybe most of you) are thinking, “so what and who cares?” Well, here is why it’s important to you: God has revealed Himself to us to be a loving communion of Persons: Father, Son, and Holy Spirit.  You and I are created in that image and likeness – His image and likeness. 

You and I are invited into be part of that loving communion that is the inner life of God, and not just after we die and go to heaven.  We are called to be a part of it right now.

The family: husbands, wives, mothers, fathers, children – a loving communion of persons. 

The church: a loving communion of persons who are sons of daughters of the Father through baptism.

Our friends, our acquaintances, our neighborhoods, our towns, our cities, our country, our world – it is all supposed to be a loving communion of persons in God.

But it isn’t always, and we know that, and so it is our task to work to make it so.