When angry, the Prophet advised saying: 'A'udhu billahi minash-shaytanir-rajim' — I seek refuge in Allah from the accursed Shaytan. He also advised that if standing, sit down; if sitting, lie down; and to make wudu, as anger is from Shaytan and water extinguishes fire.
أَعُوذُ بِاللَّهِ مِنَ الشَّيْطَانِ الرَّجِيمِ
A'udhu billahi minash-shaytanir-rajim.
Meaning: I seek refuge in Allah from the accursed Shaytan.
Source: Sahih al-Bukhari #6048The Prophet (peace be upon him) said: 'The strong man is not the one who can wrestle, but the strong man is the one who controls himself at the time of anger' (Sahih al-Bukhari 6114). Seeking refuge from Shaytan acknowledges that extreme anger is from his whispers, and turning to Allah immediately neutralizes his influence.
أَعُوذُ بِاللَّهِ مِنَ الشَّيْطَانِ الرَّجِيمِ
Two men quarreled in the presence of the Prophet (peace be upon him) and one of them became very angry, his face turning red. The Prophet said: 'I know a word which, if he were to say it, his anger would go away. If he said: A'udhu billahi minash-shaytanir-rajim, his anger would go away.'