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.
Do not oppose the thoughts, which the enemy sows in you, but rather cut off all converse with them by prayer to God. We have not always strength enough so to oppose hostile thoughts as to stop them; on the contrary, in such attempts they frequently inflict us with a wound that is long in healing.
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.
It is impossible for the soul to be liberated from turbulent thoughts without the virtue of non-possessiveness. And without peace of the bodily senses it is impossible for the soul to have a peaceful intellect. And if it does not come into temptations it will not acquire wisdom of the Holy Spirit. And without laborious and persistence in reading, it will not come to the discernment of thoughts. And without the stillness of thoughts, the intellect cannot move to seek the hidden mysteries of God.
Be slow and dull to idle talk, but knowing and wise in hearkening to the saving words of the Holy Scriptures. Let the hearing of worldly tales be to you as a bitter taste in your mouth, but the discourse of holy men as a honeycomb (Prov. 16.24). Be eager to imitate men of disciplined habits and do not wait to be taught each thing. Strive to attain to the greater virtues, but do not neglect the lesser ones. Do not make light of a fall even if it be the most venial of faults; rather, be quick to repair it by repentance, although many others may commit a large number of faults, slight and grievous, and remain unrepentant. Judge not the sins of others, for they have a just Judge ‘Who will render every man according to his works’ (Rom. 2.6); but be master of what is your own and lighten your own burden insofar as you have the power, for he who increases his own burden will also carry it. In repentance is salvation, but folly is the death of repentance.
From this minute of his new life, the repentant sinner commences his podvig, struggle, and labor, and begins to bear the burden, the yoke. This is so essential that all the saints accept the only true path to virtue to be pain and hard work. On the contrary, lightness and ease are a sign of a false path, for the kingdom of God suffereth violence, and the violent take it by force (Matt. 11:12). Anyone who is not struggling, not in podvig, is in prelest.
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.
Remember, O my soul, the terrible and frightful wonder: that your Creator for your sake became Man, and deigned to suffer for the sake of your salvation. His angels tremble, the Cherubim are terrified, the Seraphim are in fear, and all the heavenly powers ceaselessly give praise; and you, unfortunate soul, remain in laziness. At least from this time forth arise and do not put off, my beloved soul, holy repentance, contrition of heart and penance for your sins.
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.
Therefore, let us force ourselves. Let us make a beginning and let us desire the good with all our heart. Because, even if we are not perfect, wanting to be, is the beginning of our salvation. From wanting we come, with God’s help, to struggling and from struggling one is helped in acquiring the virtues. This is why one of the fathers says, 'Give blood and receive spirit,' that is to say, 'Struggle and you will become accustomed to virtue.'