There are some souls so dead, so rotten, that they lie in their defilement without perceiving it, and can no longer clear themselves from it: everything leads them to evil, every thing reminds them of evil, even the most holy things; they always have these abominations before their eyes; like the unclean animal that is accustomed to live in filth, that is happy in it, that rolls itself and goes to sleep in it, that grunts in the mud; these persons are an object of horror in the eyes of God and of the holy angels.
— St. Jean Marie Vianney, Catechism on Impurity, from The Spirit of the Curé of Ars, translated by a priest of the Oratory of St. Philip Neri, 1865