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.
Those who have sinned must not despair. Let that never be. For we are condemned not for the multitude of evils, but because we do not want to repent...
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...
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…
It is vain that some unenlightened people seek the greatest evil for man somewhere else, rather than in sin. Some consider disease to be the greatest evil, others - poverty, and others - death. But neither disease, nor poverty, nor death, nor any other earthly disaster can be such a great evil for us as sin is. These earthly misfortunes do not separate us from God if we are seeking Him sincerely, but, on the contrary, they bring us closer to Him.
The only thing God requires of us is that we do not sin. But this is achieved, not by acting according to the law, but by carefully guarding the divine image in us and our supernal dignity. When we thus live in our natural state, wearing the resplendent robe of the Spirit, we dwell in God and God dwells in us. Then we are called gods by adoption and sons of God, sealed by the light of the knowledge of God.
Use your body, I beseech you, with moderation. Remember, with this body you will be raised from death when you come to be judged. Perhaps you have some doubt whether this could happen. If so, reflect in detail on what has already happened with your own self. Tell me, where were you a hundred years ago? Cannot the Creator who gave existence to a person that did not exist bring to life again to a person that did exist but is now dead? Every year He makes the corn spring to life that had withered and dies after it was sown. Do you suppose that He who raised Himself from the dead for our sake will have difficulty in raising us to new life? Or look at the trees. For a number of months they remain without fruit, even without leaves. But once the winter is past, they become green all over, new, as if risen from the dead. With better reason, and with greater ease shall we be called to new life. Do not listen to those who deny the resurrection of the body. Isaiah testifies: ‘The dead shall live again: the bodies of those who have died shall live.’ (Isa. 26:19) And according to the word of Daniel, ‘Many of those who sleep beneath the earth shall awaken, some to life eternal, the rest to eternal ruin.’ (Dan. 12:2)
What is it that commends our own life? Is it miracles, or is it a life scrupulously and uprightly lived? It is rather from the latter that miracles arise, and to that they tend. For he that lives a worthy life, draws this grace upon himself; and whosoever receives such graces receives them that he may help others to amend their lives. For even Christ wrought miracles that He might the more be accepted as worthy of belief, and so might the more attract men to Himself, and by this means bring sanctity into their lives.