St. Peter of Damascus teaches, 'When joy comes, represent sorrow to yourself; and when you are encompassed by sorrow, try to awaken joy.' Thus you will be safeguarded both against deception and against despair.
Whenever in your path you find unchanging peace, beware: you are very far from the divine paths trodden by the weary feet of the saints. For as long as you are journeying in the way to the city of the Kingdom and are drawing near the city of God, this will be a sign for you: the strength of the temptations that you encounter. And the nearer you draw close and progress, the more temptations will multiply against you.
But when the Holy Spirit dwells in the heart of a person, He shows him all his inner poverty and weakness, and the corruption of his heart and soul, and his separation from God; and with all his virtues and righteousness. He shows him his sins, his sloth and indifference regarding the salvation and good of people his self-seeking in his apparently most disinterested virtues, his coarse selfishness even where he does not suspect it. To be brief, the Holy Spirit shows him everything as it really is. Then a person begins to have true humility, begins to lose hope in his own powers and virtues, regards himself as the worst of men. And when a person humbles himself before Jesus Christ Who alone is Holy in the glory of God the Father, he begins to repent truly, and resolves never again to sin but to live more carefully. And if he really has some virtues, then he sees clearly that he practiced and practices them only with the help of God, and therefore he begins to put his trust only in God.
The fact that repentance furnishes hope should not be taken by us as a means to rob ourselves of the feeling of fear, so that one might more freely and fearlessly commit sin. For behold how God in every wise preached fear in all the Scriptures and showed Himself to be a hater of sin.
Be despised and rejected in your own eyes, and you will see the glory of God within yourself. For where humility blossoms, there God’s glory bursts forth.
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.
The man who has found love eats and drinks Christ every day and hour and so is made immortal. 'Whoever eats of this bread', He says, 'which I will give him, will never taste death.' Blessed is he who consumes the bread of love, which is Jesus! He who eats of love eats Christ, the God over all, as John bears witness, saying, 'God is love.'
Do not be surprised that when you draw near to virtue, grievous and intense tribulations come to you on all sides: for virtue is not considered virtue, if it does not involve hard work.
Do not approach the words of the mysteries contained in the divine Scriptures without prayer and beseeching God for help, but say: 'Lord, grant me to perceive the power in them!' Reckon prayer to be the key to the true understanding of the divine Scriptures.
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.