Vision of Saint Catherine of Sienna on impurity

Dialogue with God The Father
"(...) those unhappy men do not only check such tendency, but that they do something much worse and they fall in the vice against the nature. They are blind and stupid, whose confused intelligence does not perceive the vileness in which they live.
I displease this last sin, because I am the Eternal Purity. It is to Me so abominable that by its cause I made disappear five cities. (cf. Genesis 19, 24). My Justice is not able to support it more.
That sin, nevertheless, does not only dislike to Me. It is even unbearable to the demons, who are had by patterns by those unfortunate ministers.
The demons do not tolerate that sin. They do not wish the virtue, but by his angelical origin, they challenge to see so stinking vice.
They throw the poisoned arrows of lust, but they turn round at the moment at which the sin is committed ".(Saint Catherine of Sienna. The Dialogue)

Santa Caterian da Siena e San Bernardino da Siena, addirittura affermano che la sodomia è il peccato più grave, dopo quello contro lo Spirito Santo e, comunque, se la sodomia è praticata con persistenza, in violazione dei dettami di Dio, anch'esso diventa peccato a cui non c'è perdono: “…Commettendo il maledetto peccato contro natura, quali ciechi e stolti, essendo offuscato il lume del loro intelletto, non conoscono il fetore e la miseria in cui sono…” (S. Caterina da Siena, Dialogo della Divina Provvidenza, cap. 124)