Sin, to one who loves God, is nothing other than an arrow from the enemy in battle. The true Christian is a warrior fighting his way through the regiments of the unseen enemy to his heavenly homeland.
How great the evil of pride is, that it deserves to have as its adversary not an angel or other virtues contrary to it but rather God Himself! For it must be noted that it is never said of those who are caught up in the other vices that the Lord resists them, or that the Lord is set against the gluttonous, or fornicators, or the angry, or the avaricious; this is true of the proud alone. For those vices only turn back upon wrongdoers or seem to be committed against those who have a part in them -- that is, against other human beings. This one, however, of its very nature touches God, and therefore it is specially worthy of having God opposed to it.
If we remember that thief who, for a single confession, was taken into Paradise, we shall realize that it was not for the merit of the life he lived that he obtained so great blessedness, but that it was his by the gift of God, Who had mercy on him. Or let us think of David, the king, whose two such grievous and awful crimes were wiped away by one word of penitence. Neither here do we see that the merit of what he did was equal to obtaining pardon for such great offense, but the grace of God did the more abound when on the occasion of true penitence He did away with all that weight of sin for one single word of genuine confession. Again, when we consider the beginnings of man's calling and salvation, which, as the Apostle tells us, is not of ourselves or of our words, but we are saved by the gift and grace of God, we shall be able clearly to perceive how the end of perfection is not 'of him that willeth, nor of him that runneth, but of God Who showeth mercy,' Who makes us victors over our vices, although we have no merit at all of life or labors to weigh against them, nor does the effort of our will avail for us to reach the steep summit of righteousness, or to subdue the flesh which we are bound to use... For the outcome of all good flows from His grace, Who hath bestowed so great an eternity of bliss and such immeasurable glory, with manifold generosity, upon the weak will and the short life-work of man.
Do all in your power not to fall, for the strong athlete should not fall. But if you do fall, get up again at once and continue the contest. Even if you fall a thousand times because of the withdrawal of God's grace, rise up again each time, and keep on doing this until the day of your death. For it is written, 'If a righteous man falls down seven times' - that is, repeatedly throughout his life - 'seven times shall he rise again' [Prov. 24:16].
For never is a man forced into sin by another’s fault, unless he have, stowed away in his heart, matter for evil deeds. Nor is a man to be held a victim of sudden deception if at the sight of a woman’s beauty he fall into an abyss of vile lust. Rather is it that diseases of soul, deeply hidden away and lost to view, come then to the surface on the occasion of the sight.
Cultivate patience. Patience is a heavenly gift, a gift from the Heavenly Father... With patience, and love for your fellow men, you become a victor in life's continual trials.
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.
I shall speak first about control of the stomach, the opposite to gluttony, and about how to fast and what and how much to eat. I shall say nothing on my own account, but only what I have received from the Holy Fathers. They have not given us only a single rule for fasting or a single standard and measure for eating, because not everyone has the same strength; age, illness or delicacy of body create differences. But they have given us all a single goal: to avoid over-eating and the filling of our bellies... A clear rule for self-control handed down by the Fathers is this: stop eating while still hungry and do not continue until you are satisfied.
Exercise patience out of love for your fellow man. Exercise patience in order to benefit your soul. For if you do not take your soul into consideration, you lose your patience.
If the base of a felled tree that has grown old in the earth and rock ‘will bud at the scent of water . . . like a young plant’ (Job 14:9), it is also possible for us to be awakened by the power of the Holy Spirit and to flower with the incorruptibility that is ours by nature, bearing fruit like a young plant, even though we have fallen into sin.
Fire makes iron impossible to touch, and likewise frequent prayer renders the intellect more forceful in its warfare with the enemy. That is why the demons strive with all their strength to make us slothful in attentiveness to prayer, for they know that prayer is the intellect's invincible weapon against them.