In the heart is the will; in the heart is love; in the heart is the mind--in the heart is the image of the divine Trinity. The heart is the home of the Father, the altar of the Son and the workshop of the Holy Spirit. God wants our hearts: Son, give Me thy heart. Oh, my brother, above and beyond all else that you keep safe, guard your heart. Let the mountains be overthrown and the seas dried up; let friends forsake you and riches betray you; let your body be eaten by worms; let the world pour on you all the scorn of which it is capable--and do not fear. Only guard your heart; guard it and make it cleave to the Lord; give it into His keeping. Life flows from the heart; but whence comes this life in the heart, unless it is the abode of the breath of the Lord and Source of life-God? Oh, my brother, the Spirit of God Himself can, when He so desires, dwell in the human heart. He not only can, but wills to do so. Only, He waits for you to prepare your heart for Him; to make it into a temple, for God the Holy Spirit only lives in a temple. As a snake protects its head, so, my son, guard your heart. For the life that comes from the living God enters into it and flows forth from it.
As earth thrown over it extinguishes a fire burning in a stove, so worldly cares and every kind of attachment to something, however small and insignificant, destroy the warmth of the heart which was there at first.
In preparing for battle, however, do not think that you will always be victorious. Often there will be only hardship that will bring nothing but affliction... Provide yourself with only one thing, strong courage: no matter what happens, stay with what you have begun... No matter how life goes, whatever successes and failures there are, you should give all of this over to God's will.
Not every man is wakened to wonder by what is said spiritually and has great power concealed in it. A word concerning virtue has need of a heart unbusied with the earth and its converse.
According to the teaching of the Fathers, any impression which, touching the heart, fills it with a great irritation, must come from the region of passions. Therefore impulses which spring from the heart should not be followed at once, but only after careful examination and fervent prayer. God preserve us from a blind heart! It is well known that passions do blind the heart and screen the shining sun of the mind that we should all strive to gaze at.
In the matter of piety, poverty serves us better than wealth, and work better than idleness, especially since wealth becomes an obstacle even for those who do not devote themselves to it. Yet, when we must put aside our wrath, quench our envy, soften our anger, offer our prayers, and show a disposition which is reasonable, mild, kindly, and loving, how could poverty stand in our way? For we accomplish these things not by spending money but by making the correct choice. Almsgiving above all else requires money, but even this shines with a brighter luster when the alms are given from our poverty. The widow who paid in the two mites was poorer than any human, but she outdid them all.
Accordingly, a man will neither be puffed up through pride, nor cast down by despair, if he uses the good things divinely bestowed on him, to the glory of the Giver; withholding his desires from the things which he knows will hurt him. And so he that would preserve himself from the wickedness of envy, from the corruption of sensuality, from the unrest of anger, from the desire of revenge, will be purified by the sanctifying power of true abstinence, and will taste the joy of imperishable delights, so that by making spiritual use of them, he will learn to change earthly possessions into heavenly, not by storing what he has received, but by multiplying more and more that which he has been given.
As long as the flesh is in full health, let us observe abstinence at all times and in every place. When it has been tamed (which I do not suppose is possible this side of the grave), then let us hide our accomplishment.
Just as we must beware of overeating, so too we must beware of excessive temperance or abstinence. Excessive temperance weakens the body, destroys wakefulness, coolness and freshness which are indispensable for vigilance, and which fade and weaken when the physical powers succumb and fail. If you force a weak body to labor beyond its powers, you subject your soul to double darkness, and lead it into confusion (and not relief)...
Stint your stomach and you will certainly lock your mouth, because the tongue is strengthened by an abundance of food. Struggle with all your might against the stomach and restrain it with all sobriety. If you labor a little, the Lord will also soon work with you.
Courage does not consist in defeating and oppressing one's neighbor, for this is overbearingness, which oversteps the bounds of courage. Nor again does it consist in fleeing terrified from the trials that come as a result of practicing the virtues; for this is cowardice and falls short of courage. Courage itself consists in persisting in every good work and in overcoming the passions of soul and body. For our struggle is not against flesh and blood, that is, against men, as was the case with the Jews of old, where to conquer other nations was to do the work of God; it is against principalities and powers, that is, against the unseen demons (Ephesians 6:12). He who is victorious conquers spiritually; otherwise he is conquered by the passions. The warfare described in the Old Testament prefigures our spiritual warfare. These two passions of overbearingness and cowardice, though they appear to be opposites, are both caused by weakness. Overbearingness pulls one upwards and is outwardly something startling and frightening, like some powerless bear, while cowardice flees like a chased dog. No one who suffers from either of these two passions puts his trust in the Lord, and therefore he cannot stand firm in battle, whether he is overbearing or cowardly. But the righteous man is as bold as a lion (Proverbs 28:1) in Christ Jesus our Lord, to whom be glory and dominion throughout the ages.
Intemperance and attachment to things cause torrents of passions to flood the soil of the heart and deposit there all the mud and filth of thoughts, thus confusing the mind, darkening the heart and weighing down the body. In the heart and the soul they produce negligence, darkness and death and deprive them of the feeling and disposition natural to them.