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…
Of the Only Case in Which Anger is Good... But we have a use for anger most properly planted within us, and for this use alone it is profitable and healthful for us to entertain it, namely, when we burn with wrathful indignation against the lustful motions of our own hearts, and are enraged to find that those things which we should be ashamed to do or to speak of before men have found admittance into the secret places of our minds. We may then well dread and fear exceedingly the presence of the Angels and the Omnipresence of God Himself, and His all-seeing Eye from which no secrets of our hearts can lie hid.
Those who have acquired genuine prayer experience an ineffable poverty of the spirit when they stand before the Lord, glorify and praise Him, confess to Him, or present to Him their entreaties. They feel as if they had turned to nothing, as if they did not exist. That is natural. For when he who is in prayer experiences the fullness of the divine presence, of Life Itself, of Life abundant and unfathomable, then his own life strikes him as a tiny drop in comparison to the boundless ocean. That is what the righteous and long-suffering Job felt as he attained the height of spiritual perfection. He felt himself to be dust and ashes; he felt that he was melting and vanishing as does snow when struck by the sun's burning rays (Job 42:6).
When someone is beginning the spiritual life, he should not study a lot, but instead watch himself and guard his thoughts. A strong person is the one who chews well, not the one who eats a lot.
When walking in the way of righteousness, it is impossible not to meet with trouble, or that the body should not suffer pain and weakness and should remain immutable, if we want to live in virtue.
We must with unflagging zeal and care give ourselves to the pursuit of virtue, and constantly occupy ourselves in its practice, lest at any time progress may cease, and regress immediately take its place.... To cease to acquire means to lose, for the will which goes no longer forward will not be far from peril of falling back.
It is, indeed, impossible for the mind not to be troubled by thoughts, but accepting them or rejecting them is possible for everyone who makes an effort...therefore we practice the frequent reading of Scripture, so that we may be open to a spiritual point of view. For this reason we frequently chant the psalms, so that we may continually grow in compunction. For this reason we are diligent in vigils, fasting, and praying, so that the mind which has been stretched to its limits may not taste earthly things but contemplate heavenly ones. When these things cease because negligence has crept in again, then, it is inevitable that the mind, by the accumulated filth of the vices, will soon turn in a carnal direction and fall.
By holy baptism original sin is expunged, as also sins committed before baptism. It also eliminates the violent power sin has over us till rebirth; it gives us the grace of the Holy Spirit by which we are united with God in Christ, and we receive power to subdue and conquer sin. For the simple reason that we are not delivered from the struggle with sin, we cannot be entirely free from sin during the whole of our earthly life, and even the righteous man may fall seven times (i.e. often) and rise again by repentance, says Scripture (Prov. 24:16). He falls on account of his weakness and limitations, because he does not always notice sin which subtly and imperceptibly rears its head from his fallen nature, and which is artfully and imperceptibly offered and suggested by fallen spirits. Repentance becomes his secure possession, his constant weapon, his invaluable treasure. By repentance the righteous man maintains his fellowship with Christ. He is healed by repentance from the wounds caused by sin.
Temptations are sent for improvement when God delivers his righteous ones to various temptations, humiliating them for some slight and unimportant offense, or to increase their purity, in order that every uncleanliness of thought, or... dross which He sees they have harbored in secret, may be burnt away in this present life, and that so He may bring them, as it were pure gold, to the future judgment...
The belly when filled with all kinds of food gives birth to seeds of wantonness, nor can the mind, when choked with the weight of food, keep the guidance and government of the thoughts. For not only is drunkenness with wine wont to intoxicate the mind, but excess of all kinds of food makes it weak and uncertain, and robs it of all its power of pure and clear contemplation. The cause of the overthrow and wantonness of Sodom was not drunkenness through wine, but fullness of bread. Hear the Lord rebuking Jerusalem through the prophet. 'For how did thy sister Sodom sin, except in that she ate her bread in fullness and abundance?' (Ezek. xvi. 49)