Fasting Out of Rage

There is also another evil kind of resentment, which would not be worth mentioning were it not that we know some of the brothers allow it. When they have been vexed or enraged, they actually go on stubbornly refusing food. So (a thing we cannot mention without shame) those who, when they are calm, declare that they cannot possibly put off their meal until the sixth or at most the ninth hour, do not even feel a fast of two days when they are filled with resentment and rage. And when they are exhausted by such abstinence, they keep themselves going on a glut of anger. In this they are plainly guilty of the sin of sacrilege. For out of the devil’s own rage they endure fasts that ought especially to be offered to God alone, out of desire for humbling of heart and cleansing from sin. This is much the same as if they were to offer prayers and sacrifices not to God but to demons, and so deserve to hear this rebuke of Moses: “They sacrificed to demons and not to God, to gods whom they did not know.” [a]