If you happen to be wounded by succumbing to some sin through weakness, or through the faulty nature of your character (I mean here pardonable sins: an unfitting word has slipped out, you lost your temper, a bad thought flashed in your head, an unfitting desire flared up, and so on), do not lose heart and fall into sense-less turmoil. Above all do not dwell on yourself, do not say: “How could I be such as to allow and suffer it?” This is a cry of proud self-opinion. Humble yourself and, raising your eyes to the Lord, say and feel: “What else could be expected of me, O Lord, weak and faulty as I am.” Thereupon give thanks to Him that the thing has gone no further, saying: “If it were not for Thy boundless mercy, O Lord, I would not have stopped at that, but would certainly have fallen into something much worse.”

With this feeling and consciousness of yourself you must not, however, admit the self-indulgent and heedless thought that since you are what you are, you have as it were a right to behave wrongly. No, in spite of the fact that you are weak and faulty, you are accounted guilty for all the wrong things you do. For since you possess a will, all that comes forth from you is subject to it, and so everything good is counted in your favour and everything bad—to your detriment. Therefore, conscious of your general wickedness, admit yourself guilty also in the particular wicked-ness, into which you have fallen at the present moment. Judge and condemn yourself, and only, yourself; do not look around, seeking on whom you could put the blame. Neither the people around you nor the circumstances are guilty of your sin. Your bad will alone is to blame. So blame yourself. 

—Lorenzo Scupoli, Unseen Warfare