St. John Chrysostom

We have anger, not to insult those close to us, but to return sinners to the way of God, to rise when we fall, so that we are not sluggish. Anger is given to us like a sting, to gnash our teeth against the devil, to be impulsive against him and not to rebel against each other. We have weapons to use against the enemy. Are you irritable? To be such against your sins, to rebuke your soul, to plague your conscience, to be a strict judge and bitter judge of your own sins. This is the gain of rage. That is why God put it in us.

(Bad) anger is a willful demon, a willful rage, a lack of logic. Angry is the game of the devil, the lab of demons, a worthy servant of their wickedness. If you want to be angry, do not do this against your fellow man, but against the evil demon. You have where to put your passion. Never reconcile with him, empty your anger into him, set a trap for him and never get tired of fighting him. So anger is not a sin, but evil and unjustified anger. That is why the Prophet David said the following: "Be angry, but do not sin"!