CATECHISM OF THE CATHOLIC CHURCH
SECOND EDITION

Paragraphs 412–416

412 But why did God not prevent the first man from sinning? St. Leo the Great responds, "Christ's inexpressible grace gave us blessings better than those the demon's envy had taken away." And St. Thomas Aquinas wrote, "There is nothing to prevent human nature's being raised up to something greater, even after sin; God permits evil in order to draw forth some greater good. Thus St. Paul says, 'Where sin increased, grace abounded all the more'; and the Exsultet sings, 'O happy fault,. . . which gained for us so great a Redeemer!'"
413 "God did not make death, and he does not delight in the death of the living. . . It was through the devil's envy that death entered the world" (Wis 1:13; 2:24).
414 Satan or the devil and the other demons are fallen angels who have freely refused to serve God and his plan. Their choice against God is definitive. They try to associate man in their revolt against God.
415 "Although set by God in a state of rectitude man, enticed by the evil one, abused his freedom at the very start of history. He lifted himself up against God, and sought to attain his goal apart from him" (GS 13 § 1).
416 By his sin Adam, as the first man, lost the original holiness and justice he had received from God, not only for himself but for all human beings.