'Abdallah b. Mas'ud reported God’s messenger as saying, "He who beats the cheeks, tears the front of the garments, and cries out as people did in pre-Islamic times, does not belong to us." (Bukhari and Muslim.)

وَعَنْ عَبْدِ اللَّهِ بْنِ مَسْعُودٍ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «لَيْسَ مِنَّا مَنْ ضَرَبَ الْخُدُودَ وَشَقَّ الْجُيُوبَ وَدَعَا بِدَعْوَى الْجَاهِلِيَّةِ»