Anger as a form of temporary madness
Nahj al-Balāgha|Volume 1|Book 3|Chapter 255
٢٥٥. وَقَالَ (عليه السلام): الْحِدَّةُ ضَرْبٌ مِنَ الْجُنُونِ، لاِنَّ صَاحِبَهَا يَنْدَمُ، فَإِنْ لَمْ يَنْدَمْ فَجُنُونُهُ مُسْتَحْكِمٌ.
255. Amīr al-mu’minīn, peace be upon him, said: Anger is a kind of madness because the victim to it repents afterwards. If he does not repent his madness is confirmed.