"How incomprehensible are the judgements of God; how unsearchable His ways!"
Today the Church year is half over. Today concludes not only the Easter season, but almost the entirety of the Church's presentation of the history of our salvation. Ever since Advent, the Masses of the various seasons have represented all of the ages of the earth -- from Adam and Eve, throughout the four-thousand years of waiting for the coming of the Messias (in Advent), through His birth and the events of His early life (in the Christmas season), through the events of His public life (in the weeks after Epiphany and Lent), through His Last Supper, Passion, Death, and Resurrection, His Ascension into heaven, and finally with the descent of the Holy Ghost at Pentecost.
To observe this half way point, the Church has us observe this feast of the Holy Trinity, to commemorate the very special revelation that there is a trinity of Persons in one God. I say that it is a "very special revelation," because it is one of the great mysteries of our Faith. While it is not contradictory or illogical, it is simply something that we could never have guessed at through the unaided powers of our natural reason.
Even though God had befriended the Jewish people, making them His own, and revealing to them the intricacies of His law and the way in which He wanted to be worshipped, He gave them no more than clues that He might be anything other than one Person. To be sure, we read of "the Spirit of God moving over the waters" in Genesis1; and of "the Spirit of wisdom, and understanding, of counsel and strength, and knowledge and fear of the Lord" in Isaias2; and in the Psalms we learn that "by the Word of the Lord the heavens were made.... for He spoke and [the earth] was made, He commanded and it stood forth."3 Perhaps there are other clues, but none of them, separately or taken together, is adequate to make us imagine that the Father, the Word, and the Spirit might be separate Persons in the one God.
It is only with the coming of Jesus Christ that we begin to fathom the truth of the matter: With the angel saying to Mary, "the Holy Ghost shall come upon thee, and the power of the Most High shall overshadow thee, and the Holy to be born of thee shall be called the Son of God" (in St. Luke's Gospel),4 with the voice of the Father saying, both at the Baptism and the Transfiguration of our Lord, that "This is My beloved Son in whom I am well pleased" (in Matthew's Gospel)5. Only in the New Testament do we learn that "In the beginning was the Word, and the Word was with God, and the Word was God.... and through Him all things were made.... and the Word became flesh and dwelt amongst us."6 The are other passages, of course, but you have all heard them before and will hear them again over the course of the Church's year.
The point is that God has told us something about Himself that cannot be known except through His divulging it to us. We human beings usually come to know things through our experience. We know the things that we can see and touch and smell and hear -- sometimes, we are willing to accept such things on the testimony of others -- we may be willing to reason to the existence of something unseen by examining the evidence it leaves behind. We can know many things, including the existence of God Himself, through the evidence of creation -- but the Trinity leaves no direct evidence, and can't be touched or seen or otherwise sensed -- we know it only because God has favored us with the knowledge of His inner self. Here again we see the working of our adoption as sons and daughters of God.
Over the centuries, theologians have taken our knowledge of the Trinity, and tried to understand how such a thing might be, and what might be its implications. In today's Divine Office we read the Athanasian Creed, a rather complex explanation of the Trinity:
There are other Creeds and other explanations, some a little more difficult to understand, some a little less. But it may well be beyond us to understand a mystery in such great detail -- after all, it is a mystery. If anything, our reaction to the mystery ought to be one of the will, rather than one of the intellect. God loves us and has taken us into His confidence, much like a father revealing the secrets of his family to his children.
We have spent roughly a half year in learning about the history of our salvation --today begins the second half of the Church year -- time less for learning about our salvation, and more for working out that salvation in practice. A time for making disciples of all nations, beginning, of course, with ourselves.
1. Genesis i: 2.