5 And first let us inquire for what cause Jesus came down. Now mind not my argumentations, for perhaps you may be misled but unless thou receive testimony of the Prophets on each matter, believe not what I say: unless thou learn from the Holy Scriptures concerning the Virgin, and the place, the time, and the manner, receive not testimony from man. For one who at present thus teaches may possibly be suspected: but what man of sense will suspect one that prophesied a thousand and more years beforehand? If then you seek the cause of Christ's coming, go back to the first book of the Scriptures. In six days God made the world: but the world was for man. The sun however resplendent with bright beams, yet was made to give light to man, yea, and all living creatures were formed to serve us: herbs and trees were created for our enjoyment. All the works of creation were good, but none of these was an image of God, save man only. The sun was formed by a mere command, but man by God's hands: Let us make man after our image, and after our likeness. A wooden image of an earthly king is held in honour; how much more a rational image of God?
But when this the greatest of the works of creation was disporting himself in Paradise, the envy of the Devil cast him out. The enemy was rejoicing over the fall of him whom he had envied: would you have had the enemy continue to rejoice? Not daring to accost the man because of his strength, he accosted as being weaker the woman, still a virgin: for it was after the expulsion from Paradise that Adam knew his wife.
Source: Catechetical Lectures (New Advent)