Genesis 3

The conclusion is that the devil would not have begun by an open and obvious sin to tempt man into doing something that God had forbidden, had not man already begun to seek satisfaction in himself and consequently to take pleasure in the words "you shall be as gods." The promise of these words, however, would much more truly have to pass if, by obedience, Adam and Eve had kept close to the ultimate and true source of their being and had not, by pride, imagined that they were themselves the source of their being.… Whoever seeks to be more than he is becomes less. Whenever he aspires to be self-sufficing, he retreats from the One who is truly sufficient for him.

It was not in order to see outward things that "their eyes were opened," because they could see such things already. It was in order that they might see the difference between the good they had lost and the evil into which they had fallen. That is why the tree is called the tree of the knowledge of good and evil. They had been forbidden to touch it because if they did it would bring on the experience of this distinction. It takes the experience of the pains of sickness to open our eyes to the pleasantness of health.

As soon as our first parents had disobeyed God's commandment, they were immediately deprived of divine grace and were ashamed of their nakedness. They covered themselves with fig leaves, which perhaps were the first thing noticed by the troubled pair. The parts covered remained unchanged except that previously they occasioned no shame. They felt for the first time a movement of disobedience in their flesh, as though the punishment were meant to fit the crime of their own disobedience to God. The fact is that the soul, which had taken perverse delight in its own liberty and disdained the service of God, was now deprived of its original mastery over the body. Because it had deliberately deserted the Lord who was over it, it no longer bent to its will the servant below it, being unable to hold the flesh completely in subjection as would always have been the case, if only the soul had remained subject to God. From this moment on, then, the flesh began to lust against the spirit. With this rebellion we are born, just as we are doomed to die and because of the first sin to bear, in our members and vitiated nature, either the battle with or defeat by the flesh.

Insofar as he as yet had no experience of the divine severity, Adam could be deceived in believing that his transgression was merely venial. And therefore he was at least not deceived in the same way that Eve was. He was merely mistaken concerning the judgment that would follow his attempt to excuse himself: "The woman you placed at my side gave me fruit from the tree, and I ate." To summarize briefly: though not equally deceived by believing the serpent, they equally sinned and were caught and ensnared by the devil.