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.
Charity, temperance, contemplation, and prayer please God; gluttony, licentiousness, and what multiplies them, please the flesh. Therefore they who are in the flesh cannot please God. And they that are Christ’s have crucified their flesh with the passions and concupiscences.
What is the source from which man's will can draw suitable principles of guidance? For a non-believer, an answer to this is extremely difficult and essentially impossible. Are they to be drawn from science? In the first place, science is interested primarily in questions of knowledge and not morals, and secondly, it does not contain anything solid and constant in principles because it is constantly changing. From philosophy? Philosophy teaches about the relativity of its truths and does not claim their unconditional authority. From practical life? Even less. This life itself is in need of positive principles which can remove from it unruly and unprincipled conditions. But while the answer to the present question is so difficult for non-believers, for a believing Christian the answer is simple and clear. The source of good principles is God's will, and this is revealed to us in the Savior's teaching, in His Holy Gospel. It alone has an unconditional, steadfast authority in this regard; and it alone teaches us self-sacrifice and Christian freedom, Christian equality and brotherhood (a concept stolen by those outside the Faith). The Lord Himself said of true Christians, 'Not everyone who says to Me, Lord, Lord, will enter the kingdom of heaven, but he who does the will of My Father' (Matt. 7:21).
It is up to us now to either bury our conscience under the ground, or to have it shine forth and illuminate us if we obey it. When our conscience says to us, 'Do this,' and we treat it with contempt, or it says it again and we refuse, then we are trampling it down, burying it under ground. Thus, it cannot speak to us clearly because of the weight upon it.
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…
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.
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.'