It is a very serious matter [1121D] for the heart to be bound to a habit of pleasures, and much effort is needed to cut off completely the spread of evils. Therefore, do not accustom your thinking to a familiarity with the pleasures of the thoughts, for in the assemblage of evils there burns a fire. Giving you warmth in this way, they have you reckon that it is an effort to master the fire of one’s nature, and the time of perseverance is lengthy and the life of abstinence is burdensome; and they bring back to you memories of the shameful fantasies that they suggested during the night, forming before you burning images of error. Then, having ignited in your flesh an even more intense burning, they introduce within you by means of the law of sin the notion that so far as you do not have the strength to restrain the force of your nature, even if you sin today by necessity, tomorrow you will repent for the sake of the commandment (cf. Rom. 7:23-5); for the law is humanitarian and forgives the iniquities of those who repent. And they present you with the example of certain people [1124A] who fell off in their abstinence and in turn repented, in order from these examples to render credible the counsel of their own deceit. Thus, after restoring the soul by a reverse repentance, they make the temples of chastity into a place of fornication. In this way, the double-tongued serpents of the thoughts hiss within the troubled workplace of the heart.
23. You, man of abstinence, [1124B] do not get hooked on the bait of uncertain hopes under the pretext of a new repentance, for many have fallen and were immediately snatched away, and others were unable to recover, for they were bound by the habit of pleasure as though they were under a law. How do you know, fellow, whether you will live to repent, that you ascribe years of life to yourself? And here, in committing a fault, you indulge your flesh; rather grant yourself the remembrance of death and depict for your heart the terrifying penalty of judgement, (to see) if you should be able at all to extinguish the feverish mind of the flesh (cf. Rom. 8:6).
-Evagrius of Pontus, “To Eulogios, On the Confession of Thoughts and Counsel in Their Regard,” in Evagrius of Pontus: The Greek Ascetic Corpus, tr. by Robert E. Sinkewicz (Oxford: Oxford University Press, 2003), 48-49.