Thomas Aquinas, Compendium of Theology

The devil, who had already fallen into sin, saw that man was so equipped that he could arrive at everlasting happiness, from which the devil himself had been cast out. Yet, as he knew, man could still sin. So he sought to lead man astray from the straight path of justice, by attacking him on his weaker side; that is, he tempted the woman, in whom the gift of light or wisdom shone with a lesser brilliance. The more easily to induce her to break the command, he lyingly drove from her mind the fear of death, and promised her what man naturally desires, namely, the overcoming of ignorance. "Your eyes shall be opened," he said (Gen. 3:5); and in adding: "You shall be as gods," he held out to her the excellence of greatness. He further promised perfect knowledge, with the words: "knowing good and evil." On the part of his intellect man naturally shuns ignorance and desires knowledge; and on the part of his will, which is naturally free, he desires high station and perfection, so that he may be subject to no one, or at any rate to as few as possible.