Providence and the scandal of evil

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.
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" toward 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.
Catechism 309-310