Pope St. Leo the Great Sermons, sermon 22:On the efast of the nativity, 2:
“Let us be glad in the LORD, dearly-beloved, and rejoice with spiritual joy that there has dawned for us the day of ever-new redemption. of ancient preparation(7), of eternal bliss. For as the year rolls round, there recurs for us the commemoration(8) 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(9) 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.(1) 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(1).”
I include the below quote because it refers to the seed of Mary. This is probably an allusion to Gen 3:15, since in ancient thought, the “seed” did not come from a woman, and I can only think of Gen 3:15 where this is mentioned, plus he makes an allusion to creation at the end:
St. Ignatius of Antioch, epistle of Ignatius to the Trallians, exerpt from ch.10:
But if, as some that are without God, that is, the unbelieving, say, He became man in appearance [only], that He did not in reality take unto Him a body, that He died in appearance [merely], and did not in very deed suffer, then for what reason am I now in bonds, and long to be exposed to(8) the wild beasts? In such a case, I die in vain, and am guilty of falsehood(10) against the cross of the Lord. Then also does the prophet in vain declare, “They shall look on Him whom they have pierced, and mourn over themselves as over one beloved.”(11) These men, therefore, are not less unbelievers than were those that crucified Him. But as for me, I do not place my hopes in one who died for me in appearance, but in reality. For that which is false is quite abhorrent to the truth. Mary then did truly conceive a body which had God inhabiting it. And God the Word was truly born of the Virgin, having clothed Himself with a body of like passions with our own. He who forms all men in the womb, was Himself really in the womb, and made for Himself a body of the seed of the Virgin, but without any intercourse of man. He was carried in the womb, even as we are, for the usual period of time; and was really born, as we also are; and was in reality nourished with milk, and partook of common meat and drink, even as we do. And when He had lived among men for thirty years, He was baptized by John, really and not in appearance; and when He had preached the Gospel three years, and done signs and wonders, He who was Himself the Judge was judged by the Jews, falsely so called, and by Pilate the governor; was scourged, was smitten on the cheek, was spit upon; He wore a crown of thorns and a purple robe; He was condemned: He was crucified in reality, and not in appearance, not in imagination, not in deceit. He really died, and was buried, and rose from the dead, even as He prayed in a certain place, saying, “But do Thou, O Lord, raise me up again, and I shall recompense them.”(1) And the Father, who always hears Him,(2) answered and said, “Arise, O God, and judge the earth; for Thou shall receive all the heathen for Thine inheritance.”(3) The Father, therefore, who raised Him up, will also raise us up through Him, apart from whom no one will attain to true life. For says He, “I am the life; he that believeth in me, even though he die, shall live: and every one that liveth and believeth in me, even though he die, shall live for ever.”(4) Do ye therefore flee from these ungodly heresies; for they are the inventions of the devil, that serpent who was the author of evil, and who by means of the woman deceived Adam, the father of our race."