A selected quote from the Catechism of the Catholic Church in honor of the Year of Faith (October 11, 2012 - November 24, 2013)
290 "In the beginning God created the heavens and the earth": three things are affirmed in these first words of Scripture: the eternal God gave a beginning to all that exists outside of himself; he alone is Creator (the verb "create" - Hebrew bara - always has God for its subject). The totality of what exists (expressed by the formula "the heavens and the earth") depends on the One who gives it being.
291 "In the beginning was the Word. . . and the Word was God. . . all things were made through him, and without him was not anything made that was made." The New Testament reveals that God created everything by the eternal Word, his beloved Son. In him "all things were created, in heaven and on earth.. . all things were created through him and for him. He is before all things, and in him all things hold together." The Church's faith likewise confesses the creative action of the Holy Spirit, the "giver of life", "the Creator Spirit" (Veni, Creator Spiritus), the "source of every good".
292 The Old Testament suggests and the New Covenant reveals the creative action of the Son and the Spirit, inseparably one with that of the Father. This creative co-operation is clearly affirmed in the Church's rule of faith: "There exists but one God. . . he is the Father, God, the Creator, the author, the giver of order. He made all things by himself, that is, by his Word and by his Wisdom", "by the Son and the Spirit" who, so to speak, are "his hands". Creation is the common work of the Holy Trinity.
293 Scripture and Tradition never cease to teach and celebrate this fundamental truth: "The world was made for the glory of God." St. Bonaventure explains that God created all things "not to increase his glory, but to show it forth and to communicate it", for God has no other reason for creating than his love and goodness: "Creatures came into existence when the key of love opened his hand." The First Vatican Council explains:
This one, true God, of his own goodness and "almighty power", not for increasing his own beatitude, nor for attaining his perfection, but in order to manifest this perfection through the benefits which he bestows on creatures, with absolute freedom of counsel "and from the beginning of time, made out of nothing both orders of creatures, the spiritual and the corporeal. . ."309 If God the Father almighty, the Creator of the ordered and good world, cares for all his creatures, why does evil exist? To this question, as pressing as it is unavoidable and as painful as it is mysterious, no quick answer will suffice. Only Christian faith as a whole constitutes the answer to this question: the goodness of creation, the drama of sin and the patient love of God who comes to meet man by his covenants, the redemptive Incarnation of his Son, his gift of the Spirit, his gathering of the Church, the power of the sacraments and his call to a blessed life to which free creatures are invited to consent in advance, but from which, by a terrible mystery, they can also turn away in advance. There is not a single aspect of the Christian message that is not in part an answer to the question of evil.
310 But why did God not create a world so perfect that no evil could exist in it? With infinite power God could always create something better. But with infinite wisdom and goodness God freely willed to create a world "in a state of journeying" towards its ultimate perfection. In God's plan this process of becoming involves the appearance of certain beings and the disappearance of others, the existence of the more perfect alongside the less perfect, both constructive and destructive forces of nature. With physical good there exists also physical evil as long as creation has not reached perfection.
311 Angels and men, as intelligent and free creatures, have to journey toward their ultimate destinies by their free choice and preferential love. They can therefore go astray. Indeed, they have sinned. Thus has moral evil, incommensurably more harmful than physical evil, entered the world. God is in no way, directly or indirectly, the cause of moral evil. He permits it, however, because he respects the freedom of his creatures and, mysteriously, knows how to derive good from it:
For almighty God. . ., because he is supremely good, would never allow any evil whatsoever to exist in his works if he were not so all-powerful and good as to cause good to emerge from evil itself.
312 In time we can discover that God in his almighty providence can bring a good from the consequences of an evil, even a moral evil, caused by his creatures...
314 We firmly believe that God is master of the world and of its history. But the ways of his providence are often unknown to us. Only at the end, when our partial knowledge ceases, when we see God "face to face", will we fully know the ways by which - even through the dramas of evil and sin - God has guided his creation to that definitive sabbath rest for which he created heaven and earth.