As soon as you realize that you have sinned against the Lord, add no more wounds to your bruises. But if as a human you fall again, don't get despondent, don't despair. For how will the living Lord, Who told Peter to forgive seventy times seven in a day, not forgive us?
I shall speak first about control of the stomach, the opposite to gluttony, and about how to fast and what and how much to eat. I shall say nothing on my own account, but only what I have received from the Holy Fathers. They have not given us only a single rule for fasting or a single standard and measure for eating, because not everyone has the same strength; age, illness or delicacy of body create differences. But they have given us all a single goal: to avoid over-eating and the filling of our bellies... A clear rule for self-control handed down by the Fathers is this: stop eating while still hungry and do not continue until you are satisfied.
Any soul which has lost its peace must repent, and the Lord will forgive its sins, and then peace and joy will visit the soul. There need be no witnesses, for the Holy Spirit is the witness of the remission of sins. Here is a sign of forgiveness: if you have come to hate sin, then the Lord has forgiven your sin.
If you wish that God should speedily give you hearty faith in prayer, strive with all your heart to speak and to do everything in regard to other people sincerely, and never be deceitful in your dealings with them. If you are straightforward and truthful with others, then God will give you straightforwardness and sincere faith also in reference to Himself.
For forgiveness of sins is most efficaciously prayed for with almsgiving and fasting, and supplications that are winged by such aids mount swiftly to God’s ears; since it is written, 'the merciful man doeth good to his own soul' (Prov. xi. 17), and nothing is so much a man’s own as that which he spends on his neighbor. For that part of his material possessions with which he ministers to the needy, is transformed into eternal riches, and such wealth is begotten of this bountifulness as can never be diminished or in any way destroyed, for 'blessed are the merciful, for God shall have mercy on them' (Matt. v.7), and He himself shall be their chief Reward, who is the Model of His own command.
According to St. Gregory the Sinaite there are three degrees in eating: temperance, sufficiency, and satiety. Temperance is when someone wants to eat some more food but abstains, rising from the table still somewhat hungry. Sufficiency is when someone eats what is needed and sufficient for normal nourishment. Satiety is when someone eats more than enough and is more than satisfied. Now if you cannot keep the first two degrees and you proceed to the third, then, at least, do not become a glutton, remembering the words of the lord: 'Woe unto you that are full now, for you shall hunger' (Lk. 6:25). Remember also that rich man who ate in this present life sumptuously every day, but who was deprived of the desired bosom of Abraham in the next life, simply because of this sumptuous eating.
Let us be satisfied simply with what sustains our present life, not with what pampers it. Let us pray to God for this, as we have been taught, so that we may keep our souls unenslaved and absolutely free from domination by any of the visible things loved for the sake of the body. Let us show that we eat for the sake of living, and not be guilty of living for the sake of eating. The first is a sign of intelligence, the second proof of its absence.
Imagine, picture the multitude of your sins and imagine how tolerant of them is the Master of your life, while you are unwilling to forgive your neighbor even the smallest offense. Moan and bewail your foolishness, and that obstruction within you will vanish like smoke, you will think more clearly, your heart will grow calm, and through this you will learn goodness, as if not you yourself had heard the reproaches and indignities, but some other person entirely, or a shadow of yourself.
An elder prescribes the following rule of conduct for the monastic table: 'When you sit to eat, brother, do not be overcome by the demon of gluttony, which compels you to eat in a disorderly way and in haste and to desire to taste many kinds of food together. Learn to eat modestly and in an orderly way and maintain a measure of restraint.'