Abû Hurayrah radhiyallahu ta'ala ‘anh relates that a man said to the Prophet sallallahu 'alaihi wasallam, “Counsel me.” The Prophet sallallahu 'alaihi wasallam said: “Do not get angry.” The man repeated his request many times, but the Prophet sallallahu 'alaihi wasallam kept saying: “Do not get angry.” [ Sahîh al-Bukhârî ]
The importance of this hadith
By limiting his counsel to this one short instruction, the Prophet sallallahu 'alaihi wasallam indicates the importance of controlling one's anger, and that doing so has far-reaching implications for a person's welfare both in the worldly life and in the Hereafter.
The emotion of anger
Anger is a very powerful emotion. It rages through a person, creating a desire for revenge and for striking out at the object of anger. Anger is an emotion that inspires action, and the action that it inspires is one of injury. The emotion of anger invokes within a person the very antithesis of mercy, compassion, self-restraint, and kindness.
This is what makes the emotion so dangerous. If left unchecked and uncontrolled, it is the emotion that can lead a person to the evilest of deeds and to the worst and most tragic consequences.
Prevention of anger
The statement “Do not get angry”, taken on its face value, is commanding us not to experience the emotion of anger at all. We know that this cannot be the intended meaning in an absolute sense, since it is an impossible instruction to uphold. Anger is a natural, human emotion. It is impossible for a person to avoid it absolutely.
Though this hadith may not be prohibiting us from ever experiencing the emotion of anger, it is, at the very least, advising us strongly to avoid that emotion as much as possible. And, indeed, there are measures that a person can take to limit his chances of getting angry.
First, he can condition himself to remain cool-tempered. When a person's temper is under control, he is less likely to become angry when an occasion for anger arises, and more likely to control himself when he, in spite of himself, does become angry.
Another way that a person can limit his chances of getting angry is for him to know what causes anger and remove those causes from his life. Among the chief causes of anger are pride and arrogance, since a prideful person is most easily offended and the most painfully stung by criticism. Another cause of anger is being argumentative. The more a person disputes with others, the less likely he is to accept the truth. His views become increasingly polarized and emotionally charged. A Muslim is, therefore, encouraged to avoid these negative character traits. In doing so, he will be less likely to get angry.