Of the Stain of Sin

"Now man's soul has a twofold comeliness; one from the refulgence of the natural light of reason, whereby he is directed in his actions; the other, from the refulgence of the Divine light, viz. of wisdom and grace, whereby man is also perfected for the purpose of doing good and fitting actions. Now, when the soul cleaves to things by love, there is a kind of contact in the soul: and when man sins, he cleaves to certain things, against the light of reason and of the Divine law... . Wherefore the loss of comeliness occasioned by this contact, is metaphorically called a stain on the soul." --St. Thomas Aquinas, Of the Stain of Sin, from the first article