The Prophet ﷺ said, "He who slaps the cheeks, tears the clothes and follows the tradition of the Days of Ignorance is not from us." (Using translation from Bukhārī 1297)  

عَنِ النَّبِيِّ ﷺ قَالَ «لَيْسَ مِنَّا مَنْ ضَرَبَ الْخُدُودَ وَشَقَّ الْجُيُوبَ وَدَعَا بِدَعْوَى الْجَاهِلِيَّةِ»