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.
Our enemies (demons) fell because of their pride, and call us to follow them, and bring us feelings of praise. And if your soul accepts that praise, then grace will depart, until the soul becomes humble again. And so all your life you must learn the humility of Christ.
The soul that is given over to the will of God fears nothing: neither thunder nor thieves nor any such thing. Whatever may come, 'Such is God's pleasure,' she says. If she falls sick she thinks, 'This means that I need sickness, or God would not have sent it.'
The Saints in Heaven through the Holy Spirit behold the glory of God and the beauty of the Lord's Countenance. But in this same Holy Spirit they see our lives too, and our deeds. They know our sorrows and hear our burning prayers. When they were living on earth they learned of the love of God from the Holy Spirit: and he who knows love on earth takes it with him into eternal life in the Kingdom of Heaven, where love grows and becomes perfect. And if love makes one unable to forget a brother here, how much more must the Saints remember and pray for us!
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.
Any soul which has lost its peace must repent, and the Lord will forgive its sins, and then peace and joy will visit the soul. There need be no witnesses, for the Holy Spirit is the witness of the remission of sins. Here is a sign of forgiveness: if you have come to hate sin, then the Lord has forgiven your sin.
Remember that a good action is always either preceded or followed by temptations. God permits this so that the virtue, exercised in that particular action, may be confirmed, consolidated, steeled.
The way to attain compunction is an attentive life. ‘The beginning of repentance comes from the fear of God and attention,’ as the holy martyr Boniface says.
Your past and present torments and sufferings are poured down upon you to test your faith and 'steel' it; they also work to curb your lusts and passions. Humble yourself. God gives help to the humble. Judgment of others, insistence on their shortcomings, can only increase the bitterness of your sorrow. Choose the better part.