Chapter 32 — Part III: The Decalogue — The Ninth and Tenth Commandments
Section 8. The law of God, therefore, is a sort of mirror, in which we behold the corruption of our own nature; and hence these words of the Apostle: I had not known concupiscence, if the law did not say: "Thou shalt not covet." ' Concupiscence, which is the fuel of sin, and which originated in sin, is always inherent in our fallen nature; from it we know that we are born in sin, and, therefore, do we humbly fly for assistance to Him, who alone can efface the stains of sin.