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.
The Martyrs won Paradise through their blood; the Ascetics, through their ascetic life. Now you, my brethren, who have children, how will you win Paradise? By means of hospitality, by giving to your brothers who are poor, blind, or lame.
If you want to cure your soul, you need four things. The first is to forgive your enemies. The second is to confess thoroughly. The third is to blame yourself. The fourth is to resolve to sin no more. If we wish to be saved, we must always blame ourselves and not attribute our wrong acts to others. And God, Who is most compassionate, will forgive us.
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.
And among all the works of God, before which the mind grows faint with awe, which so rejoices yet overwhelms the soul as the Passion of our Savior? For as often as we dwell, as best we can, upon His Omnipotence, which He shares with the Father in one and the same nature, more wondrous does His lowliness seem to us than His power; and with more difficulty do we grasp His emptying Himself of the divine Majesty, than His sublime uplifting of the form of a servant.
The holy Fathers' counsel is to begin with small things, for, says Ephraim the Syrian, how can you put out a great fire before you have learned to quench a small one? If you wish to set yourself free from a great suffering, crush the small desires, say the holy Fathers. Do not suppose that the one can be separated from the others: they all hang together like a long chain or a net.
I beseech you, put this to the test. When a man affronts you or brings dishonor on your head, or takes what is yours, or persecutes the Church, pray to the Lord, saying: 'O Lord, we are all Thy creatures. Have pity on Thy servants and turn their hearts to repentance,' and you will be aware of grace in your soul. To begin with, constrain your heart to love enemies, and the Lord, seeing your good will, will help you in all things, and experience itself will show you the way. But the man who thinks with malice of his enemies has not God's love within him, and does not know God.
Train yourself to cut off an intrusive thought immediately…Be at pains over this, so that you acquire the habit. The soul is a creature of habit: according to the habit you have acquired, so will you act all the rest of your life.
Where there is pride there cannot be grace, and if we lose grace we also lose both love of God and assurance in prayer. The soul is then tormented by evil thoughts and does not understand that she must humble herself and love her enemies, for there is no other way to please God.
If you refuse to accept suffering and dishonor, do not claim to be in a state of repentance because of your other virtues. For self-esteem and insensitivity can serve sin even under the cover of virtue.
But if you are fearful of becoming self-righteous from working for your own salvation, or afraid of being overcome by spiritual pride, examine yourself and observe that the person who is afraid of becoming self-righteous suffers from blindness. For he does not see how self-righteous he is.
Apostolic teaching, Beloved, exhorts us that we put off the old man with his deeds (Eph. iv. 22; Col. iii. 9), and renew ourselves from day to day by a holy manner of life. For if we are the temple of God, and if the Holy Spirit is a Dweller in our souls, as the Apostle says: You are the temple of the living God (II Cor. vi. 16); we must then strive with all vigilance that the dwelling of our heart be not unworthy of so great a Guest.