‘Let not the sun go down upon your wrath: neither give place to the devil’ (Eph. iv. 26-27).
The devil has no access to the soul, if the soul itself harbours no passions. In such a state it is transparent and the devil cannot see it. But when it admits the movement of a passion and consents to this movement, it becomes darkened and the devil sees it. He approaches it boldly and assumes control over it. Two evil passions principally trouble the soul–lust and irritability. When the devil means to captivate someone through lust, he leaves him alone in this turmoils: the devil does not bother him any more, except perhaps to disturb him a little with anger. But if a man does not give in to lust, the devil hasten to incite him to anger, and gathers round him a quantity of irritating things. A man who fails to discern the devil’s wiles allows himself to become annoyed at everything, permitting anger to master him, and so he ‘give place to the devil.’ But a man who stilfes every upsurge of anger resists the devil and repels him, and gives no place to him within himself. Anger ‘gives place to the devil,’ as soon as it is regarded as something just and its satisfaction is felt to be lawful. Then the enemy immediately enters the soul and begins to suggest thoughts, each more irritating than the last. The man starts to be aflame with anger as though he were on fire. This is the fire of hell; but the poor man thinks that he is burning with zeal for righteousness, whereas, there is never any righteousness in wrath (James i. 20). This is the form of illusion [prelest] peculiar to wrath, just as there is another form of illusion [prelest] peculiar to lust. A man who speedily overcomes wrath disperses this illusion and thus repels the devil as though by a strong blow in the chest. Is there anyone who, after extinguishing his anger and analysing the whole business in good faith, does not find that there was something wrong at the basis of his irritation? But the enemy changes the wrong into a sense of self-righteousness and builds it up into such a mountain that is seems as though the whole world would go to pieces if our indignation is not satisfied.
You say that you cannot help being resentful and hostile? Very well then, be hostile–but towards the devil, not towards your brother. God gave us wrath as a sword to pierce the devil–not to drive into our own bodies. Stab him with it, then, right up to the hilt; press the hilt in as well if you like, and never pull it out, but drive another sword in as well. This we shall achieve by becoming gentle and kind towards each other. ‘Le me lose my money, let me destroy honour and glory–my fellow-member is more precious to me than myself.’ Let us speak thus to each other, and let us not injure our own nature in order to gain money or fame.
–St. Theophan the Recluse (in Igumen Chariton of Valamo, The Art of Prayer [Faber & Faber, 1966], pp. 211-212)