Trinity Sunday, Year C
First Reading: Prv 8:22-31 
Second Reading: Rom 5:1-5 
Gospel Reading: Jn 16:12-15 
“There is only one true God, eternal, infinite, and unchangeable, incomprehensible, almighty, and ineffable, the Father and the Son and the Holy Spirit; three Persons indeed, but one essence, substance, or nature,” says the Catechism of the Catholic Church.

I used to hear every year the legend of how St. Augustine, walking along the seashore meditating on the Trinity, was rebuked by a child, who said it would be easier to pour the whole ocean into a hole in the sand. It suggested to me that it was a waste of time for me even to think about the Holy Trinity.

However, the Catechism calls this doctrine “the central mystery of Christian faith and life” and “the most fundamental and essential teaching in the hierarchy of the truths of faith.”

The explanation is that “at the heart of the divine act of creation is the divine desire to make room for created persons in the communion of the uncreated Persons” of the Holy Trinity. That is why God made us. And if we are to spend eternity in that communion, we should learn something about it.

A teacher I know says he insists that his students use words correctly to describe concepts. For example, if they talk about “the voltage going through a light bulb,” he makes them say, instead, “the voltage across a light bulb.” Without the right words, he says, they cannot acquire the right concept.

How much more important it is to use words correctly about the Holy Trinity, even if we never fully understand what we are saying. For example, it is not right to throw out the names “Father,” “Son,” and “Holy Spirit” (used by Christ himself) and substitute “Creator,” “Redeemer,” and “Sanctifier.”

For one thing, the latter suggest that one Person of the Blessed Trinity creates us, a second redeems us, and the third sanctifies us. No; there is only “one will and one operation with which the most Holy Trinity creates, arranges, and governs” everything outside itself. The only distinctions among the Persons lie in their relations to each other.

Accordingly, Jesus says in this Sunday’s Gospel Reading, “All that the Father has is mine;” the Spirit of truth “will take what is mine and declare it to you.”

We can never understand fully the nature of the “incomprehensible” God, but we can come to understand him better.

Analogies can help. One of the best, for me, is contained in Dorothy Sayers’ play Zeal of Thy House.

“Every work of creation is threefold, an earthly trinity to match the heavenly,” the Archangel Michael says at the end.

“First: there is the creative idea; passionless, timeless, beholding the whole work complete at once, the end in the beginning; and this is the image of the Father.

“Second: there is the creative energy, begotten of that idea, working in time from the beginning to the end, with sweat and passion, being incarnate in the bonds of matter; and this is the image of the Word.

“Third: there is the creative power, the meaning of the work and its response in the lively soul; and this is the image of the indwelling Spirit.

“And these three are one, each equally in itself the whole work, whereof none can exist without other; and this is the image of the Trinity.”

We can see this “earthly trinity” in any human creation. Imagine putting on a dinner: first, there is the idea of the meal, the menu as planned; second, the work of buying, preparing, and serving the food; and third, its consumption by the guests.

Each can equally be called “the dinner.” However, the dinner could not be said to have “come off” if any one of them were missing. Nevertheless, there is only one dinner.

God has made us in his own image, a maker and craftsman like himself, a little mirror of his triune majesty.