It is impossible for the mind to escape disturbing thoughts, but it is possible, for any who take sufficient care, either to admit them or reject them.
Sometimes, when we are overcome by pride or impatience and are unwilling to amend our ill-conditioned and disordered way of life, we complain that what we need is solitude, as though in solitude, meeting with no provocation, we should find there the virtue of patience, making excuses for our slackness, and laying the blame of our agitation not upon our own lack of patience, but ascribing it to the faults of our brethren, whereas so long as we impute to others the causes of our own faults, we shall never be able to reach the goal of patience and of perfection.
Such are the souls of the saints: they love their enemies more than themselves, and in this age and in the age to come they put their neighbor first in all things, even though because of his ill-will he may be their enemy.
That prayer may be poured forth with that fervor and singleness of heart that it ought to have, these rules must always be observed. In the first place, anxiety concerning the things of the flesh must be altogether be put away; then we must not allow to enter our minds any thought or even memory of worldly cares or business. We must cut off slanderings, vain words or many words, jestings and the like. We must root out the disturbances of anger especially, and despondency, and also tear up the
evil roots of carnal lust and avarice. And so with these and similar faults done entirely away with and cut off, - things which can also be discerned by human eyes - and with such a cleansing and purifying as we have mentioned first carried out in the sincerity of simplicity and innocence, we must lay the unshakable foundations of humility strong enough to sustain a tower which shall pierce the heavens.
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.
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.
The first duty of a Christian, of a disciple and follower of Jesus Christ, is to deny oneself. To deny oneself means to give up one's bad habits, to root out of the heart all that ties us to the world; not to cherish bad desires and thoughts; to quench and suppress bad thoughts; to avoid occasions of sin; not to do or desire anything from self-love but to do everything out of love for God. To deny oneself means, according to the Apostle Paul, to be dead to sin and the world, but alive to 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.
Rivalry over material possessions has made us forget the counsel of the Lord, who urged us to take no thought for earthly things, but to seek only the kingdom of heaven (cf. Matt. 6:33).
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.
It's difficult to be saved in the world amidst the seductions and the customs of this world that go counter to the Holy Church. Evil communications corrupt good manners (I Cor. 15:33). It's difficult to be saved in the midst of dissolute society. In the Holy Scriptures it is said, With the holy man wilt thou be holy, and with the innocent man wilt thou be innocent. And with the elect man wilt thou be elect, and with the perverse wilt thou be perverse (Ps. 17:25-6).
The more a man struggles to do good, the more fear grows in him, until it shows him his slightest faults, those which he thought of as nothing while he was still in the darkness of ignorance.
The road into the Kingdom of Heaven was made by the Lord Jesus Christ, and He was the first one who traveled it. The Bible teaches that only he who follows Jesus can reach His Kingdom. But how can one follow Him? Hear what our Savior says about this: Whoever desires to come after Me, let him deny himself, and take up his cross, and follow Me (Mark 8:34). The words whoever desires mean that Christ does not compel anyone to follow Him. He has no need of the unwilling ones, but He desires that each person freely follow Him. Consequently, only those who willingly choose the Savior's path reach the Kingdom of Heaven.
A mind that dwells on everyday matters of life and vain things disperses the soul. One should turn inwardly, looking at the soul’s uncultivated vineyard, weeding it of all evil thorns and planting virtues there instead. But be wary, for this type of work is not easy at all. It requires perseverance and much patience. One will be confronted with a multitude of difficulties. Various writings of the Fathers are very helpful, and in our days are available by the dozens. In them one can find anything his heart desires, and anything it needs. The Fathers will lead you on the right spiritual path, if only you read them with humility and prayer.