Man’s first sin
397 Man, tempted by the devil, let his trust in his Creator die in his heart and, abusing his freedom, disobeyed God’s command. This is what man’s first sin consisted of. All subsequent sin would be disobedience toward God and lack of trust in his goodness. (1707, 2541; 1850, 215)
398 In that sin man preferred himself to God and by that very act scorned him. He chose himself over and against God, against the requirements of his creaturely status and therefore against his own good. Constituted in a state of holiness, man was destined to be fully “divinized” by God in glory. Seduced by the devil, he wanted to “be like God,” but “without God, before God, and not in accordance with God.” (2084, 2113)
399 Scripture portrays the tragic consequences of this first disobedience. Adam and Eve immediately lose the grace of original holiness. They become afraid of the God of whom they have conceived a distorted image—that of a God jealous of his prerogatives.