Suppose you have ordered yourself not to eat fish; you will find that the enemy continually makes you long to eat it. You are filled with an uncontrollable desire for the thing that is forbidden. In this way you can see how Adam's fall typifies what happens to all of us. Because he was told not to eat from a particular tree, he felt irresistibly attracted to the one thing that was forbidden him.
A characteristic of those who are still progressing in blessed mourning is temperance and silence of the lips; and of those who have made progress – freedom from anger and patient endurance of injuries; and of the perfect – humility, thirst for dishonors, voluntary craving for involuntary afflictions, non- condemnation of sinners, compassion even beyond one’s strength. The first are acceptable, the second laudable; but blessed are those who hunger for hardship and thirst for dishonor, for they shall be filled with the food whereof there can be no satiety.
Some, for the sake of forgiveness, give themselves up to labors and struggles, but a man who is forgetful of wrongs excels them. If you forgive quickly, then you will be generously forgiven.
Until we have acquired true prayer, we are like those who introduce children to walking. Make the effort to raise up, or rather, to enclose your mind within the words of your prayer; and if, like a child, it gets tired and falters, raise it up again. The mind, after all, is naturally unstable, but the God Who can do everything can also give it firm endurance. Persevere in this, therefore, and do not grow weary...
If in time of trial a man does not patiently endure his affliction, but cuts himself off from the love of his spiritual brethren, he does not yet possess perfect love or a deep knowledge of divine providence.
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.
Pray simply. Do not expect to find in your heart any remarkable gift of prayer. Consider yourself unworthy of it. Then you will find peace. Use the empty cold dryness of your prayer as food for your humility. Repeat constantly: I am not worthy; Lord, I am not worthy! But say it calmly; without agitation.
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.
When we are incapable of scaling the peaks of virtue, all we have to do is to descend into the ravine of humility. Our humility is our surest intercessor before the face of the Lord.