From Pope St. John Paul II’s encyclical Veritatis Splendor (1993):
Not only the world, however, but also man himself has been entrusted to his own care and responsibility. God left man “in the power of his own counsel” (Sir 15:14), that he might seek his Creator and freely attain perfection. Attaining such perfection means personally building up that perfection in himself. Indeed, just as man in exercising his dominion over the world shapes it in accordance with his own intelligence and will, so too in performing morally good acts, man strengthens, develops and consolidates within himself his likeness to God.
Even so, the [Second Vatican] Council warns against a false concept of the autonomy of earthly realities, one which would maintain that “created things are not dependent on God and that man can use them without reference to their Creator”.67 With regard to man himself, such a concept of autonomy produces particularly baneful effects, and eventually leads to atheism: “Without its Creator the creature simply disappears . . . If God is ignored the creature itself is impoverished”.68
67 Pastoral Constitution on the Church in the Modern World Gaudium et Spes, 36.
— Veritatis Splendor 39