What is the source of anger? how to fight or cope with anger when your relatives provoke you? thank you

Anger is usually connected with arrogance, if something doesn't go your way, or if someone bothers or offends you. The best way is to think ahead, and that way you're prepared with the most beneficial answer and won't just "react from the gut": e.g. "If my mother-in-law says this, I won't let her get me annoyed, and say to myself, that's just her prejudice". King David said when Shim'i cursed him, "Apparently he was sent by God" (Sam. II, 16), and see it as a test of fortitude. Similarly, if you were tipped off that in a prospective job interview, the boss will try and anger you, in order to see your reaction under pressure, there's no way you'd get mad. Similarly if you remember that all of life is a test, prepare yourself and you won't get angry. Remember, "everything is all for the best"!