It is more serious to lose hope than to sin. The traitor Judas was a defeatist, inexperienced in spiritual warfare; as a result he was reduced to despair by the enemy's onslaught, and he went and hanged himself. Peter, on the other hand, was a firm rock: although brought down by a terrible fall, yet because of his experience in spiritual warfare he was not broken by despair, but leaping up he shed bitter tears from a contrite and humiliated heart. And as soon as our enemy saw them, he recoiled as if his eyes had been burnt by searing flames, and he took flight...
Peter was first given the keys, but then he was allowed to fall into the sin of denying Christ; and so his pride was humbled by his fall. Do not be surprised, then, if after receiving the keys of spiritual knowledge you fall into various evil thoughts. Glorify our Lord, for He alone is wise: through setbacks of this kind He restrains the presumption that we tend to feel because of our advance in the knowledge of God. Trials and temptations are the reins whereby God in His providence restrains our human arrogance.
Therefore, if you wish to conquer the passions, cut off the love of pleasure; but if you are pursuing food, you will spend a life in passions; the soul will not be humbled if the flesh is not deprived of bread. It is not possible to deliver the soul from perdition while protecting the body from unpleasantness.
Condemn only yourself, and you will not be condemned at His second and awful coming. From your whole heart remit the sins of whoever sins before you, and your Father who is in heaven will remit your sins.
A man may seem to be silent, but if his heart is condemning others, he is babbling ceaselessly. But there may be another who talks from morning till night and yet he is truly silent, that is, he says nothing that is not profitable.
If anyone thinks that he has love but does not have the same love for all, but distinguishes between persons, separating the lowly from the rich, the infirm from the healthy, a sinner from a righteous man, one far off from one near, one who is an enemy from one who loves you, such love is not perfect, but partial. Actual and perfect love consists in considering everyone and loving them equally, both those who love you and those who hate you. Such love, with which mercy is inseparable, is, in brief, a net for all virtues. It embraces and contains all the commandments of God within itself.
Prayer is the mind's dialogue with God, in which words of petition are uttered with the intellect riveted wholly on God. For when the mind unceasingly repeats the name of the Lord and the intellect gives its full attention to the invocation of the divine name, the light of the knowledge of God overshadows the entire soul like a luminous cloud.
A great effort and much toil are needed in prayer before we can reach a state in which our mind is no longer troubled, and so attain the inward heaven of the heart where Christ dwells. As St. Paul says, 'Do you not realize that Christ dwells within you, unless you are worthless?' (cf. 2 Cor. 13:5).
Do not say...that one or two books is sufficient for instructing the soul. After all, even the bee collects honey not from one or two flowers only, but from many. Thus also he who reads the books of the Holy Fathers is instructed by one in faith or in right thinking, by another in silence and prayer, by another in obedience and humility and patience, by another in self-reproach and in love for God and neighbor; and, to speak briefly, from many books of the Holy Fathers a man is instructed in life according to the Gospel.
The humility which in due time and by God's grace, after many struggles and tears, is given by heaven to those who seek it is something incompararably stronger and higher than the sense of abasement felt by those who have lapsed from holiness. This higher humility is granted only to those who have attained true perfection and are no longer under the sway of sin.