What does Islam say about anger?

Answer 1

Surah Aal-e-Imran

Verses 133-134

وَسَارِعُوْٓا اِلٰى مَغْفِرَةٍ مِّنْ رَّبِّكُمْ وَجَنَّةٍ عَرْضُھَا السَّمٰوٰتُ وَالْاَرْضُ ۙ اُعِدَّتْ لِلْمُتَّقِيْنَ

And hasten towards protection from your Sustainer leading to the Jannah which encompasses the entire universe and has been prepared for the Muttaqeen.

(meaning those people who are concerned about welfare and maintaining and protecting of, laws of Allah.

الَّذِيْنَ يُنْفِقُوْنَ فِي السَّرَّاۗءِ وَالضَّرَّاۗءِ وَالْكٰظِمِيْنَ الْغَيْظَ وَالْعَافِيْنَ عَنِ النَّاسِ ۭ وَاللّٰهُ يُحِبُّ الْمُحْسِنِيْنَ

Namely those people (Muttaqeen) who, help the needy whether they are themselves affluent or in straitened circumstances. They sublimate their violent passions (anger) towards some constructive end and do not care how others behave towards them. (And thus maintain the balance both in themselves and the society.) Allah likes the Mohsineen.(people with balanced personalitiy).

Answer 2

A man asked the Prophet (ﷺ) for an advice and he (ﷺ) said, "Do not get angry". The man repeated that several times and he replied, "Do not get angry". (Al-Bukhari)

Messenger of Allah (ﷺ) said, "The strong man is not one who is good at wrestling, but the strong man is one who controls himself in a fit of rage." [Al-Bukhari and Muslim].