As a man cannot remain unscathed who spares his enemy on the field of battle, so a man engaged in spiritual warfare cannot save his soul if he spares his body.
Having guarded ourselves against distractions and worries, let us turn our attention to our body on which mental vigilance is completely dependent. Human bodies differ widely from one another in strength and health. Some by their strength are like copper and iron; others are frail like grass. For this reason everyone should rule his body with great prudence, after exploring his physical powers. For a strong and healthy body, special fasts and vigils are suitable; they make it lighter, and give the mind a special wakefulness. A weak body should be strengthened by food and sleep according to one's physical needs, but on no account to satiety. Satiety is extremely harmful even for a weak body; it weakens it, and makes it susceptible to disease. Wise temperance of the stomach is a door to all the virtues. Restrain the stomach, and you will enter Paradise. But if you please and pamper your stomach, you will hurl yourself over the precipice of bodily impurity, into the fire of wrath and fury, you will coarsen and darken your mind, and in this way you will ruin your powers of attention and self-control, your sobriety and vigilance…
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.
Do not approach the words of the mysteries contained in the divine Scriptures without prayer and beseeching God for help, but say: 'Lord, grant me to perceive the power in them!' Reckon prayer to be the key to the true understanding of the divine Scriptures.
If you love to enjoy true and complete delight from the Scriptures, seek to read them not merely with simple understanding, but with deeds and practical realities. Moreover, seek to read them not merely for the mere love of learning but also for the sake of ascetic endeavors & discipline, as St. Mark wrote: 'Read the words of Holy Scripture with an eye to practical applications and not merely to be puffed up by any fine thought that you may receive from it.' Another Father said: 'This is why the lover of knowledge must also be a lover of discipline. For knowledge alone does not give light to a lamp.'
The more one reads and studies the Bible, the more he finds reasons to study it as often and as frequently as he can. According to St. John Chrysostom, it is like an aromatic root, which produces more and more aroma the more it is rubbed.
When the flesh flourishes, the soul fades; when the flesh has full liberty, the soul is straitened; when the flesh is satiated, the soul hungers; when the flesh is adorned, the soul is deformed; when the flesh overflows with laughter, the soul is surrounded by misfortune; when the flesh is in the light, the soul is in darkness...
One should nourish the soul with the word of God: for the word of God, as St. Gregory the Theologian says, is angelic bread, by which are nourished souls who hunger for God. Most of all, one should occupy oneself with reading the New Testament and the Psalter, which one should do standing up. From this there occurs an enlightenment in the mind, which is in the mind, which is changed by a Divine change.
Put aside bodily considerations when you stand in prayer, lest the bite of a flea, a gnat or a fly deprive you of the greatest gain afforded by prayer.
There is a difference, Dearly Beloved Brethren, between the delights of the body and those of the soul, that the delights of the body, when we do not possess them, awaken in us a great desire for them; but when we possess them and enjoy them to the full they straightway awaken in us a feeling of aversion. But spiritual delights work in the opposite way. While we do not possess them we regard them with dislike and aversion; but once we partake of them we begin to desire them, and the more do we hunger for them. In one case the appetite pleases, the reality brings displeasure; in the other it is the appetite [that] displeases, the reality delights us more and more. In the one case appetite leads to fullness, and fullness to disgust; in the other appetite begets fullness, and fullness in turn begets appetite. For spiritual delights, when they fill the soul, increase in us a desire of them; and the more we savor them, the more do we come to know what we should eagerly love.