In order to remain in vigilance, it is necessary to guard the freshness and brightness of the mind with all care. The mind becomes darkened from imprudent use of food, drink and sleep, from much talking, from distraction and from worldly cares. Attend to yourselves, said the Lord, be on your guard and take care that your hearts are never weighed down, dulled and depressed by self-indulgence, overeating and drinking, or worldly cares and pleasures, lest that day (the day of Christ's dread judgment, the last day of the world) catch you unawares. For it will spring like a trap upon all who are living on the face of the earth. So watch and pray at all times for the strength to escape or survive all that is going to happen, and to stand before the Son of Man.
The practice of the prayer of Jesus holy David, or more accurately the Holy Spirit by the mouth of David, offers to all Christians without exception: 'The kings of the earth and all people, princes and all judges of the earth, young men and maidens - let elders with the young praise the name of the Lord, for His name alone is exalted (PS. 148:11-13).' A literal understanding of the states enumerated here would be perfectly permissible, but their essential meaning is spiritual.
Wherever we are and whatever our circumstances, the enemy always tries to prevent us from actively responding to the call. Pray for help. For help that you may never fail to respond. And beware lest, having received help and having done the right deed because of it, you should grow proud and acquire the habit of condemning others, in the secret chambers of your heart. Beware! For this would make all the fruits of your good works wither.
According to the teachings of the Holy Fathers, in order to destroy insensibility man needs a constant, patient, uninterrupted activity against insensibility; he needs a constant, pious, and attentive life.
The best medicine for pride, man’s greatest sickness of soul, is humility. Words cannot describe or explain it, but the Fathers say that he who strives hard to live according to the precepts of our Lord, and is fully aware of his own sins, acquires it steadily. Therefore be very careful never to think yourself good, or the least bit better than others.
You are, I am sure, aware that for you penitence is now no longer limited to disclosing your sins to your confessor, but that you must now bear your sins in mind always, until your heart nearly breaks with their ugly load; and would break, were it not for your firm faith in the mercy of our Lord.
Even a pious person is not immune to spiritual sickness if he does not have a wise guide -- either a living person or a spiritual writer. This sickness is called prelest, or spiritual delusion, imagining oneself to be near to God and to the realm of the divine and supernatural. Even zealous ascetics in monasteries are sometimes subject to this delusion, but of course, laymen who are zealous in external struggles (podvigi) undergo it much more frequently. Surpassing their acquaintances in struggles of prayer and fasting, they imagine that they are seers of divine visions, or at least of dreams inspired by grace. In every event of their lives, they see special intentional directions from God or their guardian angel. And then they start imagining that they are God's elect, and often try to foretell the future. The Holy Fathers armed themselves against nothing so fiercely as against this sickness -- prelest.
Fasting needn't be limited to abstinence from food alone, because true fasting is departure from evil deeds. Forgive your neighbor any insult, abstain from causing your neighbor offence, abstain from irritation, from senseless sorrows, from fear, wrath, and so on. ‘True fasting is alienation from evil, temperance of the tongue, setting aside of wrath, casting out of lust, idle talk, lies, and oath-breaking’…This is a true and pleasing fast for the Lord. Departing from these vices and from a corrupt state is what comprises a true fast.
The enemy constantly endeavors to awaken in the abyss of the human heart a great turmoil about trifles. This is one of his tricks to blind our soul to the sun of truth, Christ our Lord, hidden in the heart's core of every one of our neighbors.
Most people desire and seek after prosperity in this life, and they strive to avoid sorrows. While that seems very good and pleasant, constant prosperity and good fortune do a person harm. He falls into a variety of passions and sins, and angers the Lord, while those who live a life of sorrow come closer to the Lord and more readily attain unto salvation, for the Lord called the life of happiness the broad path. The wide gates and the broad way lead to destruction, and many there be who take that way (Matthew 7:13). It is the narrow way and the strait gate which lead to life eternal, and few there be who find it (Matthew 7:14). Thus, according to His love for us, seeing the possible benefit [of sorrows] to those who are worthy, the Lord moves many off the broad road and puts them on the narrow, sorrowful path, so that in [their] patient endurance of sickness and sorrow, He might effect their salvation and grant them life eternal.
In the grim struggle with the invisible enemies of our salvation, the supreme weapon is the prayer of Jesus. `All the nations' - the vociferous and wily demons are called nations - `surround me,' says David, `and in the name of the Lord I repulsed them. They encircled and surrounded me like bees, and they burnt like fire among thorns; and in the name of the Lord I repulsed them' (Ps. 117:10-12). With the name of Jesus flog the foes, because there is no stronger weapon in heaven or earth.
Remember always that, once we have decided consciously to strive after righteousness, we cannot escape catastrophes and sorrows, no matter where we are.