Silsilat al-Ahadith al-Sahihah

Sayyiduna Sulaiman bin Surad (may Allah be pleased with him) says: Two men began to abuse each other in the presence of the Prophet (peace and blessings of Allah be upon him). One of them became angry and his face turned red. The Prophet (peace and blessings of Allah be upon him) looked at him and said: "I know a word, if this man says it, the anger he is feeling will go away. (And that word is:) «أعوذ بالله من الشيطان الرجيم»." A man who heard this from the Prophet (peace and blessings of Allah be upon him) stood up and said to him: Do you know what the Messenger of Allah (peace and blessings of Allah be upon him) has just said? He (peace and blessings of Allah be upon him) said: "I know a word, if this man says it, his anger will go away, (and that is:) «أعوذ بالله من الشيطان الرجيم»." The man replied: Do you think I am mad?