Sahih al-Bukhari 1298
صحيح البخاري#1298SahihNarrated `Abdullah:The Prophet (ﷺ) said, "He who slaps the cheeks, tears the clothes and follows the traditions of the Days of Ignorance is not from us
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 23:56