Let's review what it is we celebrate on Trinity Sunday

The following few paragraphs are drawn from Frank Sheed's excellent introduction to the Catholic Faith, Theology for Beginners (Servant Books). Sheed had plenty more to say about the subject of the Blessed Trinity, both in this book and in his even more comprehensive Theology and Sanity (Ignatius Press), but this tasty soupçon will get you started.

I enthusiastically encourage all Catholics — indeed anybody of any background who wishes to better understand the Catholic Church's doctrine of the Trinity — to read both these books. Reading them, you will discover that, as Sheed put it, "The rewards for persistence are immense."

And for good measure, here is the old Catholic Encyclopedia's compact historical overview of the solemn feast day in honor of the Blessed Trinity:

Trinity Sunday

The first Sunday after Pentecost, instituted to honour the Most Holy Trinity. In the early Church no special Office or day was assigned for the Holy Trinity. When the Arian heresy was spreading the Fathers prepared an Office with canticles, responses, a Preface, and hymns, to be recited on Sundays.

In the Sacramentary of St. Gregory the Great (P.L., LXXVIII, 116) there are prayers and the Preface of the Trinity. The Micrologies (P.L., CLI, 1020), written during the pontificate of Gregory VII (Nilles, II, 460), call the Sunday after Pentecost a Dominica vacans, with no special office, but add that in some places they recited the Office of the Holy Trinity composed by Bishop Stephen of Liège (903-20). By others the Office was said on the Sunday before Advent.

Alexander II (1061-1073), not III (Nilles, 1. c.), refused a petition for a special feast on the plea, that such a feast was not customary in the Roman Church which daily honored the Holy Trinity by the Gloria, Patri, etc., but he did not forbid the celebration where it already existed.

John XXII (1316-1334) ordered the feast for the entire Church on the first Sunday after Pentecost. A new Office had been made by the Franciscan John Peckham, Canon of Lyons, later Archbishop of Canterbury (d. 1292).

The feast ranked as a double of the second class but was raised to the dignity of a primary of the first class, 24 July 1911, by Pius X (Acta Ap. Sedis, III, 351). The Greeks have no special feast. Since it was after the first great Pentecost that the doctrine of the Trinity was proclaimed to the world, the feast becomingly follows that of Pentecost.

Pope Gregory the Great's Warning About Wicked Shepherds

I read a mainstream media news report this morning about a recent gathering of priests and seminarians in Rome for the purpose of offering "prayers for the victims of clergy abuse and for the healing of the church's wounds from the scandal over its concealment of abuse." This is an exceedingly good thing to do, and I hope it will inspire diocesan bishops everywhere to gather their own presbyterates together and emulate this.

What caught my eye in was that article's reference to a stern warning issued by Pope Gregory the Great (A.D. 540-604) regarding those woeful shepherds (i.e., priests and bishops) who are guilty of "evil living," and acting "perversely." He denounces those who make an outward show of piety and even sanctity and yet are, inwardly, chronically corrupt and perfidious.

We are and should be fervently grateful for the many excellent, dedicated, devout and, in some cases, truly holy priests and bishops with whom we have been blessed by the Lord. I am grateful to Him for them. And yet, as we all know, in recent decades, enormous, pestilential damage has been wreaked upon innumerable souls at the hands of a group of wicked shepherds in the Catholic Church. It is about them that Pope Gregory warns in words that are worthy of our reflection.

THERE ARE SOME ALSO who investigate spiritual precepts with cunning care, but what they penetrate with their understanding they trample on in their lives: all at once they teach the things which, not by practice but by study, they have learned; and what in words they preach, by their manners they impugn.

Whence it comes to pass that when the shepherd walks through steep places, the flock follows to the precipice.

Hence it is that the Lord through the prophet complains of the contemptible knowledge of shepherds, saying, When you yourselves had drunk most pure water, you fouled the residue with your feet; and My sheep fed on that which had been trodden by your feet, and drank that which your feet had fouled Ezekiel 34:18-19.

For indeed the shepherds drink most pure water, when with a right understanding they imbibe the streams of truth. But to foul the same water with their feet is to corrupt the studies of holy meditation by evil living. And verily the sheep drink the water fouled by their feet, when any of those subject to them follow not the words which they hear, but only imitate the bad examples which they see. Thirsting for the things said, but perverted by the works observed, they take in mud with their draughts, as from polluted fountains.

Hence also it is written through the prophet, A snare for the downfall of my people are evil priests (Hosea 5:1; 9:8). Hence again the Lord through the prophet says of the priests, They are made to be for a stumbling-block of iniquity to the house of Israel. For certainly no one does more harm in the Church than one who has the name and rank of sanctity, while he acts perversely. For him, when he transgresses, no one presumes to take to task; and the offense spreads forcibly for example, when out of reverence to his rank the sinner is honored.

But all who are unworthy would fly from the burden of so great guilt, if with the attentive ear of the heart they weighed the sentence of the Truth, Whoso shall offend one of these little ones which believe in me, it were better for him that a millstone were hanged about his neck, and he were drowned in the depth of the sea (Matthew 18:6).

By the millstone is expressed the round and labor of worldly life, and by the depth of the sea is denoted final damnation.

Whosoever, then, having come to bear the outward show of sanctity, either by word or example destroys others, it had indeed been better for him that earthly deeds in open guise should press him down to death than that sacred offices should point him out to others as imitable in his wrong-doing; because, surely, if he fell alone, the pains of hell would torment him in [a] more tolerable degree (Regula Pastoralis, II).