529. Something similar is true in the case of people who are in a state of good from the Lord. If they from their will and intellect or purposefully and deliberately refrain from one evil because it is a sin, they refrain from them all; and this still more if they refrain from several. For as soon as anyone purposefully or deliberately refrains from some evil because it is a sin, he is kept by the Lord in a purpose to refrain from the rest. Consequently, if he then does evil unwittingly or under the sway of some overwhelming lust of the body, still it is not imputed to him, because he did not purpose it to himself, nor does he defend it in himself.

A person comes into this purpose if examines himself once or twice a year and repents of the evil that he finds in himself. Not so one who never examines himself.

This makes clear who it is to whom sin is not imputed, and who it is to whom it is imputed.