To act 'according to one’s strength' means to use a little less than necessary both of food, and drink, and sleep... As for food, restrain yourself when you wish to eat a little more, and in this way you will always make use of it moderately.
You know that evil entered into us through the transgression of the commandments. Hence it is obvious that by keeping them, evil departs from us. But without the doing of the commandments we should not even aspire or hope for purity of soul, because at the very outset we do not walk on the path that leads us to purity of soul. Do not say that God can give us the grace of purity of soul even without our keeping the commandments.
We have become so inattentive to the work of our salvation that we misinterpret many other words in Holy Scripture as well, all because we do not seek the grace of God and in the pride of our minds do not allow it to dwell in our souls. That is why we are without true enlightenment from the Lord, which He sends into the hearts of men who hunger and thirst wholeheartedly for God’s righteousness or holiness.
Read often and insatiably the books of the teachers of the Church on divine providence, for they lead the mind to discern the order in God’s creatures and His actions, give it strength, and by their subtleness they prepare it to acquire luminous intuitions and guide it in purity toward understanding of God’s creatures. Read also the Gospels, which God ordained for knowledge for the whole world, that you may find provisions for your journey in the might of God’s providence for every generation, and that your intellect may plunge deeply into wonder at Him. Such reading furthers your aim. Let your reading be done in a stillness which nothing disturbs; be free of all concern for the body and the turmoil of affairs, so that through the sweet understanding which surpasses all the senses you may savor that most sweet taste in your soul which she perceives in herself because of her constant intercourse with these things.
If we remember that thief who, for a single confession, was taken into Paradise, we shall realize that it was not for the merit of the life he lived that he obtained so great blessedness, but that it was his by the gift of God, Who had mercy on him. Or let us think of David, the king, whose two such grievous and awful crimes were wiped away by one word of penitence. Neither here do we see that the merit of what he did was equal to obtaining pardon for such great offense, but the grace of God did the more abound when on the occasion of true penitence He did away with all that weight of sin for one single word of genuine confession. Again, when we consider the beginnings of man's calling and salvation, which, as the Apostle tells us, is not of ourselves or of our words, but we are saved by the gift and grace of God, we shall be able clearly to perceive how the end of perfection is not 'of him that willeth, nor of him that runneth, but of God Who showeth mercy,' Who makes us victors over our vices, although we have no merit at all of life or labors to weigh against them, nor does the effort of our will avail for us to reach the steep summit of righteousness, or to subdue the flesh which we are bound to use... For the outcome of all good flows from His grace, Who hath bestowed so great an eternity of bliss and such immeasurable glory, with manifold generosity, upon the weak will and the short life-work of man.
Love of God proceeds from conversing with him; this conversation of prayer comes about through stillness, and stillness comes with the stripping away of the self.
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.
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.
The zealous are eager for ascetical struggles of self-forcing and self-opposition with the aim of self-correction, or of raising themselves to primordial purity, so that they might all the more speedily become worthy of communion with God. Obviously the more eager one is, the more diligently and longingly he does this, the sooner he achieves his goal.
The more a man struggles to do good, the more fear grows in him, until it shows him his slightest faults, those which he thought of as nothing while he was still in the darkness of ignorance.
Leaves, whether of gold or lead, placed over the eyes, obstruct the sight equally, for the value of gold does not affect the blindness it produces. Similarly, anger, whether reasonable or unreasonable, obstructs our spiritual vision.
When Christ Himself spoke to Paul and called him, He could have opened his eyes at once and made known to him the way of perfection; instead He sent him to Ananias and told him to learn from him the way of truth, saying: 'Arise and go into the city, and there you will be told what you must do' (Acts 9:6). In this manner He teaches us to be guided by those who are advanced on the way, so that the vision rightly given to Paul should not be wrongly interpreted; otherwise it might lead later generations presumptuously to suppose that each individual must be initiated into truth directly by God, as Paul was, and not by the fathers.
The body is a slave, the soul a sovereign, and therefore it is due to Divine mercy when the body is worn out by illness: for thereby the passions are weakened, and a man comes to himself; indeed, bodily illness itself is sometimes caused by the passions.
The cross is the door to mysteries. Through this door the intellect makes entrance in to the knowledge of heavenly mysteries. The knowledge of the cross is concealed in the sufferings of the cross. And the more our participation in its sufferings, the greater the perception we gain through the cross. For, as the Apostle says, `As the sufferings of Christ abound in us, so our consolation also aboundeth by Christ.'