The mystery of all mysteries is presented to us today by the true Church of Christ, namely, the mystery of the Most Holy and undivided Trinity, to which we owe the deepest honor, love and devotion.

Our belief on this subject consists principally in the three following points: there is One true God, who rewards all good deeds and punishes all evil ones, either in this world or in the next; but there are, at the same time, three Persons, who according to Holy Writ, are called, Father, Son and Holy Ghost. Each of these three Persons differs from the two others, namely the Father from the Son, the Son from the Father and the Holy Ghost, and the Holy Ghost from Father and Son. This difference of Persons implies, however, no difference in their nature; for they all possess only one divine nature and essence. Each of these Persons is true God. True God is the Father: true God, the Son: true God, the Holy Ghost. But notwithstanding this, they are not three Gods, but One God; because all three Persons possess but one divine nature. In regard to men, we say that there are as many separate and distinct natures as there are persons; but in God, as St. Augustine teaches, we find a most perfect Unity in the Trinity, and a most perfect Trinity in the Unity: this means, there is only one God, but there are three Divine Persons.

The Father is the first Person, the Son, the second, the Holy Ghost, the third. The Father has no beginning nor origin from either of the other Persons. The Son is born from all eternity, in an incomprehensible manner, of the Father, and the Holy Ghost, in an equally incomprehensible manner, proceeds from the Father and Son at the same time. And yet the Father is neither older nor higher than the Son, the Son not younger nor less than the Father, and the Holy Ghost not younger nor less than either the Father or the Son. It is true, Christ has said in the Gospel: "The Father is greater than I am:" but these words must be understood as spoken by Him in His human nature. The Father is greater than Christ as Son of man; for as such, He is not from Eternity: as He took upon Himself human nature in time, that is at His Incarnation, nearly 2000 years ago. As far, however, as His divine nature is concerned, He is equally great and eternal as the Father; and as the Father is from all eternity, so the Son by His divine nature has no beginning. The same we believe and confess of the Holy Ghost: He exists equally from all eternity.

What we believe of the eternal existence of these three divine Persons we must also believe of their other perfections, namely, of the omnipotence, omniscience, infinity and the other attributes of God. Omnipotent is the Father; omnipotent is the Son; omnipotent is the Holy Ghost. Omniscient is the Father; omniscient the Son ; omniscient the Holy Ghost Infinite is the Father; infinite the Son; infinite the Holy Ghost. Not one of these three Persons is above the other in might, wisdom, infinity, or any other perfection. One is immeasurably perfect as the other. But although each of the three Persons possesses the above named attributes, there are, nevertheless not three Gods thus perfect; as although each Person is true God, there are not three Gods, but only one ; because the three Persons possess but one divine nature. The Son of God, the second Person, possesses, besides the divine nature, also the human nature, which He took upon Himself in the virginal body of Mary, and in which He suffered and died for us. He is true God and Man. This is what the true faith teaches us of the mystery of the Most Holy Trinity.

In the Old Testament this mystery was revealed to very few and only to the most beloved friends of God; in order, as the holy Fathers write, that the Jews, who were surrounded by heathens, and who were themselves prone to idolatry, should not have an opportunity to regard the three Persons as three Gods. The Prophets impressed them only with the truth that there was only one true God and that they must worship Him alone and not turn their thoughts to the idols of the heathens. But in the New Testament, the mystery of the Holy Trinity is revealed and announced in clear words. Not to mention many passages which have reference to this, let us only regard what Christ said to His Apostles: "Going therefore, teach ye all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost."

In these words, Christ our Lord announced the three divine Persons, namely, the Father, the Son and the Holy Ghost: and at the same time their unity in one, as He does not speak in the plural, saying, in the names, but, in the name, in order to impress us with the truth, that the three Persons are but one God. To the above cited words of the Saviour, we will add those of St. John: "And there are three who give testimony in heaven, the Father, the Word and the Holy Ghost: and these three are one," namely, in their nature and essence. (John, v.) After the Gospel had been preached by the Apostles, many thousands of Jews and heathens believed this mystery, and today it is accepted in all parts of the Christian world, as an undoubted truth. It is certain that this mystery is far beyond all human comprehension, and there is no article in our faith which is more inexplicable.

What is told in regard to it of St. Augustine is well known. This holy teacher while occupied in searching into the mystery of the Holy Trinity, took a walk on the seashore, where he found a boy, who having made a small hole in the sand, poured water from the sea into it with a spoon. After watching the boy for a long time, the Saint asked him what he was doing. "I wish," replied the boy, "to pour the sea into this hole." "O my child!" said the Saint: "that is a useless attempt. So small a hole cannot contain the immense sea." "And you," replied the boy, " will be still less able to contain and comprehend, with your human understanding, the stupendous mystery of the Holy Trinity!" After these words, the child, who doubtless was an angel, vanished.

Truly this mystery is inconceivable and fathomless; yet we do right, nay more, we are bound under pain of damnation to believe it, as it is taught by Him, who can neither deceive, nor be deceived, as He is Himself eternal and infallible truth. God himself revealed it to us, and this is and must be sufficient for us to cast aside all doubts. Our understanding must, according to the exhortation of St. Paul, submit and become a prisoner in the service of faith. For, the words of God must be true, whether we comprehend them or not. And finally, why do we wonder that we are unable to fathom so great a mystery, when there are so many natural things which our understanding fails to explain? Besides, God does not command us to understand, but to believe it. "Believing is commanded to me," writes St. Augustine. "To search into the mystery of the Holy Trinity, and to wish to comprehend it," says St. Bernard, "is presumption; but to believe it is godliness." Elsewhere, he writes these memorable words: "If any one asks how the Catholic faith in regard to this point can be true, I answer, that it should be enough for any one to believe that it is so. If any one goes further and attempts to explain what he is only expected to believe, he places himself in danger of losing his faith and with it his salvation."

This was indeed the fate of many who, by their impertinent pondering, came at last so far that they protested against and denied the Most Holy Trinity.

It is unquestionable that there was no article of faith which in the early centuries was so much assailed as this one. The Jews would not admit of Three Persons in the Divinity; the heathens maintained the plurality of Gods. Some heretics professed only one Person; others denied the Divinity of Christ; and again others the Divinity of the Holy Ghost. There were some who said that the three Persons were only different names; while others taught that one Person was greater than the other, &c. The Arians, who contested the divinity of Christ, caused the greatest disturbance, the greatest evil in the Church of God, on account of their inveigling many bishops and several emperors into their false doctrines. They persecuted the Catholics, especially bishops and priests, as cruelly, and in some places, more cruelly than the heathens had done. It is known that many thousands of Catholics confirmed with their blood their faith in the Holy Trinity and in the Divinity of Christ, during the persecution of the Church by the Arians.

We read also of many astonishing miracles which God at that time wrought to confirm the truth of the Catholic Faith. In the last few centuries, almost all the errors of the ancient heretics have been renewed by the followers of Luther and Calvin, both of whom assailed the word " Trinity," and would not tolerate it. The old Catholic prayer, "Holy Trinity, One God, have mercy upon us," both rejected. The bible of Luther does not contain the important text of St. John: "There are three who give testimony, &c." He left these words out, because they lead to the conclusion that we have to believe in the Holy Trinity. Calvin taught that the words: "These three are one," were not to be applied to their unity in nature, but only to their conformity of will.

What is to be concluded from this, I leave to others to find out. The more, however, the mystery of the Most Holy Trinity was assailed by the heretics, the more it was protected and defended by the Catholic Church. The Holy Mass begins daily with the sign of the Cross, the use of which is an emphatic confession of the Holy Trinity and an appeal to the same. This sign of the Cross is made several times during the day by all true Catholics, and as often as it is made, so often is the Holy Trinity acknowledged and honored. The same is done in holy Mass by the repeated Kyrie Eleison, and further by the Angelic song of praise: "Glory be to God on high:" by the Credo, or Nicene Creed, and lastly by the Sanctus, three times repeated; Holy, holy, holy! The prayers ordained by the Catholic Church, as well for holy Mass, as for all other occasions, all end with a confession of the Holy Trinity and an invocation to the same. All hymns of praise, used in the daily office of the priests and in other devout exercises end in the same manner. As often as the priest, during holy mass, or on other occasions, blesses the people, or things for the benefit of man, so often he invokes and confesses the only true God in three Persons. Every litany begins with this invocation and acknowledgment. After every Psalm is the Holy Trinity praised and honored with the well known words: "Glory be to the Father, to the Son and to the Holy Ghost, &c."

All this, and much more, has the Catholic Church ordained to honor the Holy Trinity; and to the same end she instituted today's Festival. She requires that we celebrate it most solemnly, that we not only renew our confession of faith in the most Holy Trinity, praise and worship the only true God in three divine Persons, but also give due thanks for all the benefits granted us. One of the reasons that the first Sunday after Pentecost was chosen for this celebration, lies in the fact that the mystery of the Holy Trinity as the principal article of our faith, was not publicly preached by the Apostles until after the Holy Ghost had descended upon them.

The Lutherans celebrate today's festival with us, although this was instituted by a Pope, John XXII., and is not of such ancient date as many other feasts. Why, therefore, do they not also celebrate other feasts of the Catholic Church instituted by other Popes, and of much older date? They have again admitted into their bible the verse of St. John, which Luther had left out; but what is the reason that they do not eradicate so many errors with which their Bible is filled? The Lutherans also believe in One God and three Persons in the Holy Trinity, although this is an incomprehensible mystery, and it seems impossible to the human understanding that each Person is true God and yet all three only one God. Why, believing this, do they deny other articles of faith, especially that of the presence of Christ in the Holy Eucharist, and the transubstantiation of bread and wine into the body and blood of Jesus Christ? Why do they say, in regard to it, that it is impossible? Because they are unable to comprehend it. But the same God, who revealed the mystery of the Holy Trinity, has also revealed the other, and has commanded that we should believe the one as well as the other, under pain of eternal damnation. Whoever denies the presence of Our Lord in the blessed Sacrament, or the change of the bread and wine because it is incomprehensible, will surely soon be led to deny the greatest Mystery of them all, that of the Holy Trinity, because it is much more unfathomable! And it is just this which the Evil One tries to accomplish through heresy, in order to overthrow the pillars of the Christian faith.

You have learned the three-fold intention of the Holy Church in regard to the institution of this day's festival. Endeavor to regulate your devotions accordingly. First: renew and confess publicly your faith in the great and incomprehensible mystery of the Most Holy Trinity. Be zealous in the exercises of your religion and promise before God that you will live and die in it. Make with especial devotion and attention the sign of the holy Cross, which is an emphatic confession of your belief in the Holy Trinity, and form the resolution to avail yourself of it without hesitation, according to ancient custom, publicly on all proper occasions, especially before and after prayers.

Secondly: exert today all your strength in honor and praise of the Holy Trinity. Worship the same with the deepest humility and reverence. Invite, after the example of David, and the three companions of Daniel, not only all angels and men, but also all other created beings, to join you in praising and exalting the Holy Trinity. Say from the depth of your heart, in unison with the true Church: "Glory be to the Father, to the Son and to the Holy Ghost." "Praised and blessed be the holy and undivided Trinity, now and for all eternity." Or with the heavenly Choir; "Holy, holy, holy, is the Lord God of Sabaoth." If you have done all this, still acknowledge that your God deserves infinitely more praise, honor and glory than all created beings can bestow upon Him during all eternity.

Thirdly: recall to memory the many and great blessings which have been granted to you during your life by the Holy Trinity, and endeavor to give due thanks for them. The heavenly Father has created you, the Son has redeemed you, the Holy Ghost has sanctified you. For these and other numberless benefits, offer today humble thanks. Offer to the Holy Trinity in grateful acknowledgement, all the good deeds which have been done until now on earth and which will be done until the last day arrives: especially the many Masses which have been said and will yet be said: for by them the Holy Trinity is more honored than by all the praises of men and angels. In conclusion, recite the well-known hymn of praise; "Great God we praise thee!" or "Te Deum laudamus, &c."

Finally, let the frequent invocation of the Holy Trinity, according to the precept of the true Church, be recommended to you. To invoke the Saints and the Blessed Virgin is agreeable to God and beneficial to men; but the invocation of the Most Holy Trinity, the invocation of God is commanded. Hence we should frequently resort to it. The non-Catholics are wrong in declaring the invocation of the Saints vain, wicked and even idolatrous. It would, however, be wrong, if Catholics neglected the invocation of the Holy Trinity. The true Church teaches us, at the beginning of the litany, to invoke the three divine Persons, each separately, and afterwards, all three together under the name of Holy Trinity, and not until then, does she call on the Blessed Virgin and the Saints. She does not teach that we should turn to the Saints oftener and with more confidence than to God; much less that we should invoke them instead of the Almighty, as many non-Catholics assert, either in ignorance or malice.

May you follow the precepts and teaching of the true Church. Pray frequently to the Holy Trinity, in the words: "Holy Trinity, One God, have mercy on us!" Say this with so much greater devotion as the non-Catholics, after the example of Luther, have dispensed with this ancient prayer. And why? They rejected first the invocation of the Saints; consequently, perhaps, it is not allowed to invoke the Holy Trinity! Abhor so scandalous an error, and say, with mouth and heart: "Holy Trinity, one God, have mercy on us!" Add, if you choose, the beautiful words of St. Gregory Nazianzen: "I will not become faithless to Thee, eternal Father; I will not become faithless to Thee, O only-begotten Son! I will not become faithless to Thee, O Holy Ghost; I know whom I confessed at the time of holy baptism, whom I rejected, and to whom I devoted and submitted myself."

We offer unto the Most Holy Trinity the merits of Jesus Christ, in thanksgiving for the most precious blood which he shed in the garden for us; and by his merits we beseech the Divine Majesty for the pardon of our sins.

We offer unto the Most Holy Trinity the merits of Jesus Christ, in thanksgiving for his most dolorous death, endured upon the cross for us; and by his merits we beseech the Divine Majesty for the remission of the pains due to our sins.

We offer unto the Most Holy Trinity the merits of Jesus Christ, in thanksgiving for his unspakable charity, whereby he descended from heaven to earth, to take human flesh, and to suffer and die upon the cross for us; and by his merits we beseech the Divine Majesty to conduct our souls to heavenly glory after our death.