Sahih Bukhari Volume 8, Book 78, Hadith 6117

حَدَّثَنَا عُثْمَانُ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا جَرِيرٌ، عَنِ الأَعْمَشِ، عَنْ عَدِيِّ بْنِ ثَابِتٍ، حَدَّثَنَا سُلَيْمَانُ بْنُ صُرَدٍ، قَالَ اسْتَبَّ رَجُلاَنِ عِنْدَ النَّبِيِّ صلى الله عليه وسلم وَنَحْنُ عِنْدَهُ جُلُوسٌ، وَأَحَدُهُمَا يَسُبُّ صَاحِبَهُ مُغْضَبًا قَدِ احْمَرَّ وَجْهُهُ فَقَالَ النَّبِيُّ صلى الله عليه وسلم ‏"‏ إِنِّي لأَعْلَمُ كَلِمَةً لَوْ قَالَهَا لَذَهَبَ عَنْهُ مَا يَجِدُ لَوْ قَالَ أَعُوذُ بِاللَّهِ مِنَ الشَّيْطَانِ الرَّجِيمِ ‏"‏‏.‏ فَقَالُوا لِلرَّجُلِ أَلاَ تَسْمَعُ مَا يَقُولُ النَّبِيُّ صلى الله عليه وسلم قَالَ إِنِّي لَسْتُ بِمَجْنُونٍ‏.‏

Narrated By Sulaiman bin Sarad : Two men abused each other in front of the Prophet while we were sitting with him. One of the two abused his companion furiously and his face became red. The Prophet said, "I know a word (sentence) the saying of which will cause him to relax if this man says it. Only if he said, "I seek refuge with Allah from Satan, the outcast.' " So they said to that (furious) man, 'Don't you hear what the Prophet is saying?" He said, "I am not mad."