The enemy is within ourselves. An invisible war is taking place within us. If interior evil is defeated, then the external, weaker, foe will surrender.
Observe your thoughts, and beware of what you have in your heart and your spirit, knowing that the demons put ideas into you so as to corrupt your soul by making it think of that which is not right, in order to turn your spirit from the consideration of your sins and of God.
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.
The more one reads and studies the Bible, the more he finds reasons to study it as often and as frequently as he can. According to St. John Chrysostom, it is like an aromatic root, which produces more and more aroma the more it is rubbed.
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.
Inside us evil is at work suggesting unworthy inclinations. However, it is not in us in the same way as, to take as an example, water mixes with wine. Evil is in us without being mixed with good. We are a field in which wheat and weeds are growing separately. We are a house in which there is a thief, but also the owner. We are a spring which rises from the middle of the mud, but pours out pure water. All the same, it is enough to stir up the mud and the spring is fouled. It is the same with the soul. If the evil is spread, it forms a unity with the soul and makes it dirty. With our consent, evil is united with the soul; they become accomplices. Yet there comes a moment when the soul can free itself and remain separate again: in repentance, contrition, prayer, recourse to God. The soul could not benefit from these habits if it were always sunk in evil. It is like a marriage. A woman is united with a man and they become one flesh. But when one of them dies, the other is left alone. But union with the Holy Spirit is complete. So, let us become a single spirit with Him. Let us be wholly absorbed by grace.
When Christ Himself spoke to Paul and called him, He could have opened his eyes at once and made known to him the way of perfection; instead He sent him to Ananias and told him to learn from him the way of truth, saying: 'Arise and go into the city, and there you will be told what you must do' (Acts 9:6). In this manner He teaches us to be guided by those who are advanced on the way, so that the vision rightly given to Paul should not be wrongly interpreted; otherwise it might lead later generations presumptuously to suppose that each individual must be initiated into truth directly by God, as Paul was, and not by the fathers.
