From a Letter by S. Leo the Great to the Empress Pulcheria
No figure adequately represented the mystery of our reconciliation which had been ordained from time everlasting; for the Holy Ghost had not yet come upon the Virgin, nor had the power of the Highest overshadowed her. Not yet had Wisdom builded her house within the inviolate womb, that the Word might be made flesh: Therefore, not yet had the form of God and the form of a servant been united in one person, nor the Creator of times been born in time, nor had he by whom all things were made been brought forth among his creatures. For had not a new man, made in the likeness of sinful flesh, taken our old nature upon him, and had not he who was consubstantial with the Father vouchsafed also to be consubstantial with. his Mother, and had not he, who alone is free from sin, united our nature to his own: mankind would still be held captive under the yoke of the devil.