Chapter 29 — Part III: The Decalogue — The Sixth Commandment
Section 14. Impurity Excludes From Heaven — The first kind consists chiefly in our forming a just conception of the filthiness and evil of this sin; for such knowledge will lead one more easily to detest it. Now the evil of this crime we may learn from the fact that, on account of it, man is banished and excluded from the kingdom of God, which is the greatest of all evils.