This sermon was delivered on Christmas Day 441 by Pope Leo the Great.
I. The mystery of the Incarnation demands our joy.
Let us be glad in the LORD, dearly-beloved, and rejoice with spiritual joy for a day of new redemptoion has dawned for us, a day prepared from old, one of eternal bliss. For as the year rolls round, there recurs for us the commemoration of our salvation, which promised from the beginning, accomplished in the fulness of time will endure for ever; on which we are bound with hearts up-lifted to adore the divine mystery: so that what is the effect of GOD’s great gift may be celebrated by the Church’s great rejoicings. For GOD the almighty and merciful, Whose nature as goodness, Whose will is power, Whose work is mercy: as soon as the devil’s malignity killed us by the poison of his hatred, foretold at the very beginning of the world the remedy His piety had prepared for the restoration of us mortals: proclaiming to the serpent that the seed of the woman should come to crush the lifting of his baneful head by its power, signifying no doubt that Christ would come in the flesh, GOD and man, Who born of a Virgin should by His uncorrupt birth condemn the despoiler of the human stock. Thus in the whole and perfect nature of true man was true GOD born, complete in what was His own, complete in what was ours. And “ours” we call what the Creator formed in us from the beginning and what He undertook to repair. For what, the deceiver brought in and the deceived admitted had no trace in the Saviour Nor because He partook of man’s weaknesses, did He therefore share our faults. He took the form of a slave without stain of sin, increasing the human and not diminishing the Divine: because that “emptying of Himself” whereby the Invisible made Himself visible and Creator and LORD Of all things as He was, wished to be mortal, was the condescension of Pity not the failing of Power
II. The new character of the birth of Christ explained.
Therefore, when the time came, dearly beloved, which had been fore-ordained for men’s redemption, there enters these lower parts of the world, the Son of GOD, descending from His heavenly throne and yet not quitting His Father’s glory, begotten in a new order, by a new nativity. In a new order, because being invisible in His own nature He became visible in ours, and He whom nothing could contain, was content to be contained: abiding before all time He began to be in time: the LORD of all things, He obscured His immeasurable majesty and took on Him the form of a servant: being GOD, that cannot suffer, He did not disdain to be man that can, and immortal as He is, to subject Himself to the laws of death. And by a new nativity He was begotten, conceived by a Virgin, born of a Virgin, without paternal desire, without injury to the mother’s chastity: because such a birth as knew no taint of human flesh, became One who was to be the Saviour of men, while it possessed in itself the nature of human substance. For when GOD was born in the flesh, GOD Himself was the Father, as the archangel witnessed to the Blessed Virgin Mary: “because the Holy Spirit shall come upon thee, and the power of the most High shall overshadow thee: and therefore, that which shall be born of thee shall be called holy, the Son of God.” The origin is different but the nature like: not by intercourse with man but by the power of GoD was it brought about: for a Virgin conceived, a Virgin bare, and a Virgin she remained. Consider here not the condition of her that bare but the will of Him that was born; for He was born Man as He willed and was able. If you inquire into the truth of His nature, you must acknowledge the matter to be human: if you search for the mode of His birth, you must confess the power to be of GOD. For the LORD Jesus Christ came to do away with not to endure our pollutions: not to succumb to our faults but to heal them. He came that He might cure every weakness of oar corruptness and all the sores of our defiled souls: for which reason it behoved Him to be born by a new order, who brought to men’s bodies the new gift of unsullied purity. For the uncorrupt nature of Him that was born had to guard the primal virginity of the Mother, and the infused power of the Divine Spirit had to preserve in spotlessness and holiness that sanctuary which He had chosen for Himself: that Spirit (I say) who had determined to raise the fallen, to restore the broken, and by overcoming the allurements of the flesh to bestow on us in abundant measure the power of chastity: in order that the virginity which in others cannot be retained in child-bearing, might be attained by them at their second birth.
III. Justice required that Satan should be vanquished by GOD made man.
And, dearly beloved, this very fact that Christ chose to be born of a Virgin does it not appear to be part of the deepest design? I mean, that the devil should not be aware that Salvation had been born for the human race, and through the obscurity of that spiritual conception, when he saw Him no different to others, should believe Him born in no different way to others. For when he observed that His nature was like that of all others, he thought that He had the same origin as all had: and did not understand that He was free from the bonds of transgression because he did not find Him a stranger to the weakness of mortality. For though the true mercy of GOD had infinitely many schemes to hand for the restoration of mankind, it chose that particular design which put in force for destroying the devil’s work, not the efficacy of might but the dictates of justice. For the pride of the ancient foe not undeservedly made good its despotic rights over all men, and with no unwarrantable supremacy tyrannized over those who had been of their own accord lured away from GOD’s commands to be the slaves of his will. And so there would be no justice in his losing the immemorial slavery of the human race, were he not conquered by that which he had subjugated. And to this end, without male seed Christ was conceived of a Virgin, who was fecundated not by human intercourse but by the Holy Spirit. And whereas in all mothers conception does not take place without stain of sin, this one received purification from the Source of her conception. For no taint of sin penetrated, where no intercourse occurred. Her unsullied virginity knew no lust when it ministered the substance. The LORD took from His mother our nature, not our fault. The slave’s form is, created without the slave’s estate, because the New Man is so commingled with the old, as both to assume the reality of our race and to remove its ancient flaw.
IV. The Incarnation deceived the Devil and caused him to break the bond under which he held men.
When, therefore, the merciful and almighty Saviour so arranged the commencement of His human course as to hide the power of His Godhead which was inseparable from His manhood under the veil of our weakness, the crafty foe was taken off his guard and he thought that the nativity of the Child, Who was born for the salvation of mankind, was as much subject to himself as all others are at their birth. For he saw Him crying and weeping, he saw Him wrapped in swaddling clothes, subjected to circumcision, offering the sacrifice which the law required. And then he perceived in Him the usual growth of boyhood, and could have had no doubt of His reaching man’s estate by natural steps. Meanwhile, he inflicted insults, multiplied injuries, made use of curses, affronts, blasphemies, abuse, in a word, poured upon Him all the force of his fury and exhausted all the varieties of trial: and knowing how he had poisoned man’s nature, had no conception that He had no share in the first transgression Whose mortality he had ascertained by so many proofs. The unscrupulous thief and greedy robber persisted in assaulting Him Who had nothing of His own, and in carrying out the general sentence on original sin, went beyond the bond on which he rested(7), and required the punishment of iniquity from Him in Whom he found no fault. And thus the malevolent terms of the deadly compact are annulled, and through the injustice of an overcharge the whole debt is cancelled. The strong one is bound by his own chains, and every device of the evil one recoils on his own head. When the prince of the world is bound, all that he held in captivity is released. Our nature cleansed from its old contagion regains its honourable estate, death is destroyed by death, nativity is restored by nativity: since at one and the same time redemption does away with slavery, regeneration changes our origin, and faith justifies the sinner.
V. The Christian is exhorted to share in the blessings of the Incarnation.
Whoever then thou art that devoutly and faithfully boastest of the Christian name, estimate this atonement at its right worth. For to thee who wast a castaway, banished from the realms of paradise, dying of thy weary exile, reduced to dust and ashes, without further hope of living, by the Incarnation of the Word was given the power to return from afar to thy Maker, to recognize thy parentage, to become free after slavery, to be promoted from being an outcast to sonship: so that, thou who wast born of corruptible flesh, mayest be reborn by the Spirit of GOD, and obtain through grace what thou hadst not by nature, and, if thou acknowledge thyself the son of GOD by the spirit of adoption, dare to call GOD Father. Freed from the accusings of a bad conscience, aspire to the kingdom of heaven, do GOD’s will supported by the Divine help, imitate the angels upon earth, feed on the strength of immortal sustenance, fight fearlessly on the side of piety against hostile temptations, and if thou keep thy allegiance. in the heavenly warfare, doubt not that thou wilt be crowned for thy victory in the triumphant camp of the Eternal King, when the resurrection that is prepared for the faithful has raised thee to participate in the heavenly Kingdom.
VI. The festival has nothing to do with Sun-worship, as some maintain.
Having therefore so confident a hope, dearly beloved, abide firm in the Faith in which you are built: lest that same tempter whose tyranny over you Christ has already destroyed, win you back again with any of his wiles, and mar even the joys of the present festival by his deceitful art, misleading simpler souls with the pestilential notion of some to whom this our solemn feast day seems to derive its honour, not so much from the nativity of Christ as, according to them, from the rising of the new sun(9). Such men’s hearts are wrapped in total darkness, and have no growing perception of the true Light: for they are still drawn away by the foolish errors of heathendom, and because they cannot lift the eyes of their mind above that which their carnal sight beholds, they pay divine honour to the luminaries that minister to the world. Let not Christian souls entertain any such wicked superstition and portentous lie. Beyond all measure are things temporal removed from the Eternal, things corporeal from the Incorporeal, things governed from the Governor. For though they possess a wondrous beauty, yet they have no Godhead to be worshipped. That power then, that wisdom, that majesty is to be adored which created the universe out of nothing, and framed by His almighty methods the substance of the earth and sky into what forms and dimensions He willed. Sun, moon, and stars may be most useful to us, most fair to look upon; but only if we render thanks to their Maker for them and worship GOD who made them, not the creation which does Him service. Then praise GOD, dearly beloved, in all His works and judgments. Cherish an undoubting belief in the Virgin’s pure conception. Honour the sacred and Divine mystery of man’s restoration with holy and sincere service. Embrace Christ born in our flesh, that you may deserve to see Him also as the GOD of glory reigning in His majesty, who with the Father and the Holy Spirit remains in the unity of the Godhead for ever and ever. Amen.