Anger in itself is natural. Like the existence of the nervous system in your body. You can even direct your anger against your own sins and what cause you to fall. However, when you become angry against other people like your brothers, your friends, your colleagues, you destroy whatever good deeds you have done. You should know that this anger is the result of pride and vanity. Absolve it by love for all and true humility.
When anger comes, close your mouth and do not speak back to the person who insults you or dishonors you or tries with multiple ways to tempt you, even though you have done nothing to deserve such a treatment. Man is made to be calm and reasonable and therefore anger is never in his nature, while with love he always grows as a human being. With good and love you can calm down many, and if someone has good intentions, he can quickly become peaceful as a God’s Angel.
source: Saint Joseph the Hesychast-teachings, “Expression of Monastic Experience”, ed. I. M. Philotheou – Holy Mountain
translation Dr. Nick Stergiou