As salaam Alaykum wa rahmatullah wa barakatuhu
Anger is a de stabilizing thought. It is the most dividing emotion between friends; it takes away judgment, leads to depression, madness and wrong actions that we would repent later on when we are not angry. But why do we get angry to begin with? It is either an unexpected provocation or unexpected situation which leads to frustration and an angry response.
Prophet Muhammad (PBUH), who was sent to mankind to teach them good moral conduct, learned to control his anger toward the Unbelievers and teach them appropriate expressions. He constantly spoke against being angry. One companion asked him, Give me some short advice by virtue of which I hope for good in the life hereafter, and he said, "Don't be angry." Another person asked, what will save me from the wrath of God, and he said, "Do not express your anger." A third person asked three times, 0 Prophet of God, give me an order to do a short good deed, and he said, "Don't be angry." Once he asked a question of his companion, "Who among you do you consider a strong man?" They said, the one who can defeat so-and-so wrestler in a fight, and he said, that is not so. The one who is strong is the one who can control himself at the time of anger. He also said that anger is like fire, which destroys you from within, and it can also lead you to the fire of hell by your own expressions of anger unjustly.
