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.
Prayer offered up at night possesses a great power, more so than the prayer of the day-time. Therefore all the righteous prayed during the night, while combating the heaviness of the body and the sweetness of sleep and repelling bodily nature.
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.
