Catechism of the Catholic Church §1487 — excerpt
The sinner wounds God's honor and love, his own human dignity as a man called to be a son of God, and the spiritual well-being of the Church, of which each Christian ought to be a living stone.
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.