St. Gregory Palamas ca. 1296-1359
We are made up of a soul and body, and both soul and body consist of many members. For the soul too has members after a fashion: those parts of it concerned with growth, desiring, anger and reason. Therefore, true fasting must extend to every part, cleansing and healing them all. Fasting, brethren, gently and and kindly restores the soul to health, and that is why our Fathers imposed it on us during these days.
If we shrink from fasting in our foolishness, hell waits to punish us, to cut us down and burn us, at that time when Christ will cut in pieces anyone incapable of being healed and consign them to unquenchable fire to suffer eternal punishment. It was because we did not fast in Paradise that we were thrown out into this life full of sufferings. In the same way, if we have not fasted here or lived with as much self-restraint as we could, we shall fall into that unquenchable and unbearable hell-fire. (Homily 9.9)