Catechism of the Catholic Church §324 — excerpt
The fact that God permits physical and even moral evil is a mystery that God illuminates by his Son Jesus Christ who died and rose to vanquish evil.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.