The Lord commands all men to repent (Matt. 4:17), so that even the spiritual and those making progress should not neglect this injunction and fail to give attention to the smallest and most subtle errors.
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.
Blessed are the pure in heart, for they shall see God. Everything we do, our every objective, must be undertaken for the sake of this purity of heart. This is why we take on loneliness, fasting, vigils, work, nakedness. For this we must practice the reading of the Scripture, together with all the other virtuous activities, and we do so to trap and to hold our hearts free of the harm of every dangerous passion and in order to rise step by step to the high point of love.
It is impossible for the mind to escape disturbing thoughts, but it is possible, for any who take sufficient care, either to admit them or reject them.
That prayer may be poured forth with that fervor and singleness of heart that it ought to have, these rules must always be observed. In the first place, anxiety concerning the things of the flesh must be altogether be put away; then we must not allow to enter our minds any thought or even memory of worldly cares or business. We must cut off slanderings, vain words or many words, jestings and the like. We must root out the disturbances of anger especially, and despondency, and also tear up the
evil roots of carnal lust and avarice. And so with these and similar faults done entirely away with and cut off, - things which can also be discerned by human eyes - and with such a cleansing and purifying as we have mentioned first carried out in the sincerity of simplicity and innocence, we must lay the unshakable foundations of humility strong enough to sustain a tower which shall pierce the heavens.
Sometimes, when we are overcome by pride or impatience and are unwilling to amend our ill-conditioned and disordered way of life, we complain that what we need is solitude, as though in solitude, meeting with no provocation, we should find there the virtue of patience, making excuses for our slackness, and laying the blame of our agitation not upon our own lack of patience, but ascribing it to the faults of our brethren, whereas so long as we impute to others the causes of our own faults, we shall never be able to reach the goal of patience and of perfection.
When tested by some trial you should try to find out not why or through whom it came, but only how to endure it gratefully, without distress or rancor.
Hence, in whatever state a person is, he sometimes finds himself making pure and intense prayers. For even from that first and lowest sort, which has to do with recalling the future judgment, the one who is still subject to the punishment of terror and the fear of judgment is occasionally so struck with compunction that he is filled with no less joy of spirit from the richness of his supplication than the one who, examining the kindnesses of God and going over them in the purity of his heart, dissolves into unspeakable gladness and delight. For, according to the words of the Lord, the one who realizes that more has been forgiven him begins to love more.
A worker takes the trouble to get hold of the instruments that he requires. He does so not simply to have them and not use them. Nor is there any profit for him in merely possessing the instruments. What he wants is, with their help, to produce the crafted objective for which these are the efficient means. In the same way, fasting, vigils, scriptural meditation, nakedness and total deprivation do not constitute perfection but are the means to perfection. They are not in themselves the end point of a discipline, but an end is attained to through them.
He who wants to cross the spiritual sea is long-suffering, humble, vigilant and self-controlled. If he impetuously embarks on it without these four virtues, he agitates his heart, but cannot cross.