If however any one thinks that he is not being burned when sinning, to him the Scripture saith, Shall a man wrap up fire in his bosom, and not burn his clothes? For sin burns the sinews of the soul, and breaks the spiritual bones of the mind, and darkens the light of the heart.
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…
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.
'And forgive us our debts as we also forgive our debtors.' For we have many sins. For we offend both in word and in thought, and very many things we do worthy of condemnation; and 'if we say that we have no sin' (I Jn. 1:8), we lie, as John says...The offenses committed against us are slight and trivial, and easily settled; but those which we have committed against God are great, and need such mercy as His only is. Take heed, therefore, lest for the slight and trivial sins against you, you shut out for yourself forgiveness from God for your very grievous sins.
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...
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.