Roman Catechism 29.20

Chapter 29 — Part III: The Decalogue — The Sixth Commandment

Section 20. Impurity Blinds The Mind And Hardens The Heart — But even though the adulterer may escape the punishment of death, he does not escape the great pains and torments that often overtake such sins as his. He becomes afflicted with blindness of mind a most severe punishment; he is lost to all regard for God, for reputation, for honour, for family, and even for life; and thus, utterly abandoned and worthless, he is undeserving of confidence in any matter of moment, and becomes unfitted to discharge any kind of duty.