Let him judge of another’s sin who has not on his conscience that which condemns himself. Let him judge who does not himself do what he judges must be punished in another; lest while judging the other he passes sentence upon himself. Let him give judgment on another’s sin who is not led to deliver it by any hate, by dislike, or foolish levity.
God's Scripture gives proof in numerous passages that man must undergo many disturbances in this life; and also that many consolations are at hand. With these, a spirit of sufficient vigor and awareness of the right should overcome present discomforts and look to those things that promise everlasting joy.
Wouldest thou learn words of thanksgiving? hearken unto the Three Children, saying, 'We have sinned, we have transgressed. Thou art righteous, O Lord, in all that thou hast done unto us, because thou hast brought all things upon us by a true judgment.'(4) For to confess one's own sins, this is to give thanks with confessions unto God: a kind of thing which implies one to be guilty of numberless offenses, yet not to have the due penalty exacted. This man most of all is the giver of thanks.
You ask for some way of completely eradicating irritability. The inclination to irritability is given us to use against sin, and we were never meant to use it against our fellow men. When we do, we act contrary to our true nature.
Whether you pray with brethren or alone, try to pray not simply as a routine, but with conscious awareness of your prayer. Conscious awareness of prayer is concentration accompanied by reverence, compunction and distress of soul as it confesses its sin with inward sorrow.
Let us then not lose heart, nor be slothful or timid in prayer. Even if we have been brought down to the depths of evil, prayer can speedily draw us back.
It is necessary most of all for one who is fasting to curb anger, to accustom himself to meekness and condescension, to have a contrite heart, to repulse impure thoughts and desires, to examine his conscience, to put his mind to the test and to verify what good has been done by us in this or any other week, and which deficiency we have corrected in ourselves in the present week. This is true fasting.
For forgiveness of sins is most efficaciously prayed for with almsgiving and fasting, and supplications that are winged by such aids mount swiftly to God’s ears; since it is written, 'the merciful man doeth good to his own soul' (Prov. xi. 17), and nothing is so much a man’s own as that which he spends on his neighbor. For that part of his material possessions with which he ministers to the needy, is transformed into eternal riches, and such wealth is begotten of this bountifulness as can never be diminished or in any way destroyed, for 'blessed are the merciful, for God shall have mercy on them' (Matt. v.7), and He himself shall be their chief Reward, who is the Model of His own command.
For, just as it is good to recall one's sins, so it is also good to forget one's good deeds. Why is this? Because remembrance of our good deeds puffs us up with arrogance, whereas remembrance of our sins curbs and humbles our mind; the former makes us more sluggish, but the latter makes us more diligent. Indeed, those who do not think that they have anything good become more eager to acquire what is good, whereas those who reckon that they have stored up a great deal of merchandise, confident they have an abundance of this, do not display much zeal for obtaining more of it.
Monasticism itself is a perpetual labor of conquering passions and uprooting them in order that, being in a pure and immaculate state, one may preserve oneself before the face of God. This, then, is your task! Give your attention to it, and direct all your powers towards it.