The Resurrection of the Lord is the renewal of human nature, and the renewal, re-creation and return to immortality of the first Adam who was swallowed up by death because of sin, and through death went back to the earth from which he was formed.
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.
God smiles on the compassionate heart. Every time a beggar knocks at your door, try to perceive Christ Himself under the humble disguise. Would you, under any circumstances, let Christ knock in vain? The moral qualities of the individual beggar have nothing to do with it; that is Christ's concern, not yours. Who are you to judge your brother? Christ is using the beggar’s hand and mouth to test your compassion of Himself. Will you fail Him?
We ought not to grieve or become irritated at anything because, by frequent vexation and irritability, we form the morally and physically very injurious habit of irritability, whilst by bearing opposition with equanimity we form the good and useful habit of enduring everything calmly and patiently.