28. For we must understand that a sin is committed in three ways. For it is perpetrated either through ignorance, or infirmity, or of set purpose. And we sin more grievously from infirmity than through ignorance, but much more grievously of set purpose than from infirmity. Paul had sinned from ignorance, when he said, Who was before a blasphemer, and a persecutor, and injurious, but I obtained mercy, because 1 did it ignorantly in unbelief. [1 Tim. 1, 13] But Peter sinned through infirmity, when the single word of a damsel shook in him all that strength of faith, which he had spoken of to the Lord, and when he denied, with his voice, the Lord Whom he held firm in his heart. [Matt. 26, 69. and 33.] But because a sin of infirmity or ignorance is wiped away the more easily, as it is not wilfully committed, Paul amended by knowledge the points on which he was ignorant: and Peter strengthened the root of faith which was moved, and, as it were, withering away, by watering it with his tears. ...
