XI. And now, having purified the theatre by what has been said, let us discourse a little about the Festival, and join in celebrating this Feast with festal and pious souls. And, since the chief point of the Festival is the remembrance of God, let us call God to mind. For I think that the sound of those who keep Festival There, where is the dwelling of all the Blissful, is nothing else than this, the hymns and praises of God, sung by all who are counted worthy of that City. Let none be astonished if what I have to say contains some things that I have said before; for not only will I utter the same words, but I shall speak of the same subjects, trembling both in tongue and mind and thought when I speak of God for you too, that you may share this laudable and blessed feeling. And when I speak of God you must be illumined at once by one flash of light and by three. Three in Individualities or Hypostases, if any prefer so to call them, or persons, for we will not quarrel about names so long as the syllables amount to the same meaning; but One in respect of the Substance— that is, the Godhead. For they are divided without division, if I may so say; and they are united in division. For the Godhead is one in three, and the three are one, in whom the Godhead is, or to speak more accurately, Who are the Godhead. Excesses and defects we will omit, neither making the Unity a confusion, nor the division a separation. We would keep equally far from the confusion of Sabellius and from the division of Arius, which are evils diametrically opposed, yet equal in their wickedness. For what need is there heretically to fuse God together, or to cut Him up into inequality?
XII. For to us there is but One God, the Father, of Whom are all things, and One Lord Jesus Christ, by Whom are all things; and One Holy Ghost, in Whom are all things; yet these words, of, by, in, whom, do not denote a difference of nature (for if this were the case, the three prepositions, or the order of the three names would never be altered), but they characterize the personalities of a nature which is one and unconfused. And this is proved by the fact that They are again collected into one, if you will read— not carelessly— this other passage of the same Apostle, “Of Him and through Him and to Him are all things; to Him be glory forever, Amen.” The Father is Father, and is Unoriginate, for He is of no one; the Son is Son, and is not unoriginate, for He is of the Father. But if you take the word Origin in a temporal sense, He too is Unoriginate, for He is the Maker of Time, and is not subject to Time. The Holy Ghost is truly Spirit, coming forth from the Father indeed, but not after the manner of the Son, for it is not by Generation but by Procession (since I must coin a word for the sake of clearness); for neither did the Father cease to be Unbegotten because of His begetting something, nor the Son to be begotten because He is of the Unbegotten (how could that be?), nor is the Spirit changed into Father or Son because He proceeds, or because He is God— though the ungodly do not believe it. For Personality is unchangeable; else how could Personality remain, if it were changeable, and could be removed from one to another? But they who make “Unbegotten” and “Begotten” natures of equivocal gods would perhaps make Adam and Seth differ in nature, since the former was not born of flesh (for he was created), but the latter was born of Adam and Eve. There is then One God in Three, and These Three are One, as we have said.
XIII. Since then these things are so, or rather since This is so; and His Adoration ought not to be rendered only by Beings above, but there ought to be also worshippers on earth, that all things may be filled with the glory of God (forasmuch as they are filled with God Himself); therefore man was created and honored with the hand and Image of God. But to despise man, when by the envy of the Devil and the bitter taste of sin he was pitiably severed from God his Maker— this was not in the Nature of God. What then was done, and what is the great Mystery that concerns us? An innovation is made upon nature, and God is made Man. “He that rides upon the Heaven of Heavens in the East” of His own glory and Majesty, is glorified in the West of our meanness and lowliness. And the Son of God deigns to become and to be called Son of Man; not changing what He was (for It is unchangeable); but assuming what He was not (for He is full of love to man), that the Incomprehensible might be comprehended, conversing with us through the mediation of the Flesh as through a veil; since it was not possible for that nature which is subject to birth and decay to endure His unveiled Godhead. Therefore the Unmingled is mingled; and not only is God mingled with birth and Spirit with flesh, and the Eternal with time, and the Uncircumscribed with measure; but also Generation with Virginity, and dishonour with Him who is higher than all honour; He who is impassible with Suffering, and the Immortal with the corruptible. For since that Deceiver thought that he was unconquerable in his malice, after he had cheated us with the hope of becoming gods, he was himself cheated by God's assumption of our nature; so that in attacking Adam as he thought, he should really meet with God, and thus the new Adam should save the old, and the condemnation of the flesh should be abolished, death being slain by flesh.
XIV. At His birth we duly kept Festival, both I, the leader of the Feast, and you, and all that is in the world and above the world. With the Star we ran, and with the Magi we worshipped, and with the Shepherds we were illuminated, and with the Angels we glorified Him, and with Simeon we took Him up in our arms, and with Anna the aged and chaste we made our responsive confession. And thanks be to Him who came to His own in the guise of a stranger, because He glorified the stranger. Now, we come to another action of Christ, and another mystery. I cannot restrain my pleasure; I am rapt into God. Almost like John I proclaim good tidings; for though I be not a Forerunner, yet am I from the desert. Christ is illumined, let us shine forth with Him. Christ is baptized, let us descend with Him that we may also ascend with Him. Jesus is baptized; but we must attentively consider not only this but also some other points. Who is He, and by whom is He baptized, and at what time? He is the All-pure; and He is baptized by John; and the time is the beginning of His miracles. What are we to learn and to be taught by this? To purify ourselves first; to be lowly minded; and to preach only in maturity both of spiritual and bodily stature. The first has a word especially for those who rush to Baptism off hand, and without due preparation, or providing for the stability of the Baptismal Grace by the disposition of their minds to good. For since Grace contains remission of the past (for it is a grace), it is on that account more worthy of reverence, that we return not to the same vomit again. The second speaks to those who rebel against the Stewards of this Mystery, if they are their superiors in rank. The third is for those who are confident in their youth, and think that any time is the right one to teach or to preside. Jesus is purified, and do you despise purification?...and by John, and do you rise up against your herald?...and at thirty years of age, and do you before your beard has grown presume to teach the aged, or believe that you teach them, though thou be not reverend on account of your age, or even perhaps for your character? But here it may be said, Daniel, and this or that other, were judges in their youth, and examples are on your tongues; for every wrongdoer is prepared to defend himself. But I reply that that which is rare is not the law of the Church. For one swallow does not make a summer, nor one line a geometrician, nor one voyage a sailor.
Source: Orations (New Advent)