The Oration on Holy Baptism.
I. Yesterday we kept high Festival on the illustrious Day of the Holy Lights; for it was fitting that rejoicings should be kept for our Salvation, and that far more than for weddings and birthdays, and namedays, and house-warmings, and registrations of children, and anniversaries, and all the other festivities that men observe for their earthly friends. And now today let us discourse briefly concerning Baptism, and the benefits which accrue to us therefrom, even though our discourse yesterday spoke of it cursorily; partly because the time pressed us hard, and partly because the sermon had to avoid tediousness. For too great length in a sermon is as much an enemy to people's ears, as too much food is to their bodies....It will be worth your while to apply your minds to what we say, and to receive our discourse on so important a subject not perfunctorily, but with ready mind, since to know the power of this Sacrament is itself Enlightenment.
II. The Word recognizes three Births for us; namely, the natural birth, that of Baptism, and that of the Resurrection. Of these the first is by night, and is servile, and involves passion; but the second is by day, and is destructive of passion, cutting off all the veil that is derived from birth, and leading on to the higher life; and the third is more terrible and shorter, bringing together in a moment all mankind, to stand before its Creator, and to give an account of its service and conversation here; whether it has followed the flesh, or whether it has mounted up with the spirit, and worshipped the grace of its new creation. My Lord Jesus Christ has showed that He honoured all these births in His own Person; the first, by that first and quickening Inbreathing; the second by His Incarnation and the Baptism wherewith He Himself was baptized; and the third by the Resurrection of which He was the Firstfruits; condescending, as He became the Firstborn among many brethren, so also to become the Firstborn from the dead.
III. Concerning two of these births, the first and the last, we have not to speak on the present occasion. Let us discourse upon the second, which is now necessary for us, and which gives its name to the Feast of the Lights. Illumination is the splendour of souls, the conversion of the life, the question put to the Godward conscience. It is the aid to our weakness, the renunciation of the flesh, the following of the Spirit, the fellowship of the Word, the improvement of the creature, the overwhelming of sin, the participation of light, the dissolution of darkness. It is the carriage to God, the dying with Christ, the perfecting of the mind, the bulwark of Faith, the key of the Kingdom of heaven, the change of life, the removal of slavery, the loosing of chains, the remodelling of the whole man. Why should I go into further detail? Illumination is the greatest and most magnificent of the Gifts of God. For just as we speak of the Holy of Holies, and the Song of Songs, as more comprehensive and more excellent than others, so is this called Illumination, as being more holy than any other illumination which we possess.
IV. And as Christ the Giver of it is called by many various names, so too is this Gift, whether it is from the exceeding gladness of its nature (as those who are very fond of a thing take pleasure in using its name), or that the great variety of its benefits has reacted for us upon its names. We call it, the Gift, the Grace, Baptism, Unction, Illumination, the Clothing of Immortality, the Laver of Regeneration, the Seal, and everything that is honourable. We call it the Gift, because it is given to us in return for nothing on our part; Grace, because it is conferred even on debtors; Baptism, because sin is buried with it in the water; Unction, as Priestly and Royal, for such were they who were anointed; Illumination, because of its splendour; Clothing, because it hides our shame; the Laver, because it washes us; the Seal because it preserves us, and is moreover the indication of Dominion. In it the heavens rejoice; it is glorified by Angels, because of its kindred splendour. It is the image of the heavenly bliss. We long indeed to sing out its praises, but we cannot worthily do so.
V. God is Light: the highest, the unapproachable, the ineffable, That can neither be conceived in the mind nor uttered with the lips, That gives life to every reasoning creature. He is in the world of thought, what the sun is in the world of sense; presenting Himself to our minds in proportion as we are cleansed; and loved in proportion as He is presented to our mind; and again, conceived in proportion as we love Him; Himself contemplating and comprehending Himself, and pouring Himself out upon what is external to Him. That Light, I mean, which is contemplated in the Father and the Son and the Holy Ghost, Whose riches is Their unity of nature, and the one outleaping of Their brightness. A second Light is the Angel, a kind of outflow or communication of that first Light, drawing its illumination from its inclination and obedience thereto; and I know not whether its illumination is distributed according to the order of its state, or whether its order is due to the respective measures of its illumination. A third Light is man; a light which is visible to external objects. For they call man light because of the faculty of speech in us. And the name is applied again to those of us who are more like God, and who approach God more nearly than others. I also acknowledge another Light, by which the primeval darkness was driven away or pierced. It was the first of all the visible creation to be called into existence; and it irradiates the whole universe, the circling orbit of the stars, and all the heavenly beacon fires.
VI. Light was also the firstborn commandment given to the firstborn man (for the commandment of the Law is a lamp and a light; and again, Because Your judgments are a light upon the earth); although the envious darkness crept in and wrought wickedness. And a Light typical and proportionate to those who were its subjects was the written law, adumbrating the truth and the sacrament of the great Light, for Moses' face was made glorious by it. And, to mention more Lights— it was Light that appeared out of Fire to Moses, when it burned the bush indeed, but did not consume it, to show its nature and to declare the power that was in it. And it was Light that was in the pillar of fire that led Israel and tamed the wilderness. It was Light that carried up Elias in the car of fire, and yet did not burn him as it carried him. It was Light that shone round the Shepherds when the Eternal Light was mingled with the temporal. It was Light that was the beauty of the Star that went before to Bethlehem to guide the Wise Men's way, and to be the escort of the Light That is above us, when He came among us. Light was That Godhead Which was shown upon the Mount to the disciples— and a little too strong for their eyes. Light was That Vision which blazed out upon Paul, and by wounding his eyes healed the darkness of his soul. Light is also the brilliancy of heaven to those who have been purified here, when the righteous shall shine forth as the Sun, and God shall stand in the midst of them, gods and kings, deciding and distinguishing the ranks of the Blessedness of heaven. Light beside these in a special sense is the illumination of Baptism of which we are now speaking; for it contains a great and marvellous sacrament of our salvation.
Source: Orations (New Advent)