(35) باب لَيْسَ مِنَّا مَنْ شَقَّ الْجُيُوبَ
Narrated `Abdullah:
the Prophet (ﷺ) said, "He who slaps his cheeks, tears his clothes and follows the ways and traditions of the Days of Ignorance is not one of us."
Reference: Sahih al-Bukhari 1294
In-book reference: Book 23, Hadith 53
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 2, Book 23, Hadith 382