To fast is to do violence to nature. It is to do away with whatever pleases the palate. Fasting ends lust, roots out bad thoughts, frees one from evil dreams. Fasting makes for purity of prayer, an enlightened soul, a watchful mind, a deliverance from blindness. Fasting is the door of compunction, humble sighing, joyful contrition, an end to chatter, an occasion for silence, a custodian of obedience, a lightening of sleep, health of the body, an agent of dispassion, a remission of sins, the gate, indeed, the delight of Paradise.
-Saint John Climacus