"But by the precept He gave, God commended obedience, which is, in a sort, the mother and guardian of all the virtues in the reasonable creature, which was so created that submission is advantageous to it, while the fulfillment of its own will in preference to the Creator's is destruction....This is undue exaltation, when the soul abandons Him to whom it ought to cleave as its end, and becomes a kind of end to itself. This happens when it becomes its own satisfaction. And it does so when it falls away from that unchangeable good which ought to satisfy it more than itself. This falling away is spontaneous; for if the will had remained stedfast in the love of that higher and changeless good by which it was illumined to intelligence and kindled into love, it would not have turned away to find satisfaction in itself, and so become frigid and benighted; the woman would not have believed the serpent spoke the truth, nor would the man have preferred the request of his wife to the command of God, nor have supposed that it was a venial transgression to cleave to the partner of his life even in a partnership of sin...But man did not so fall away as to become absolutely nothing; but being turned towards himself, his being became more contracted than it was when he clave to Him who supremely is. Accordingly, to exist in himself, that is, to be his own satisfaction after abandoning God, is not quite to become a nonentity, but to approximate to that. "


City of God, Book 19, Chapter 13