Sahih al-Bukhari 7562
Narrated Abu Sa`id Al-Khudri:
The Prophet (ﷺ) said, "There will emerge from the East some people who will recite the Qur'an but it will 
not exceed their throats and who will go out of (renounce) the religion (Islam) as an arrow passes 
through the game, and they will never come back to it unless the arrow, comes back to the middle of 
the bow (by itself) (i.e., impossible). The people asked, "What will their signs be?" He said, "Their 
sign will be the habit of shaving (of their beards and their heads). (Fath-ul-Bari, Page 322, Vol. 17th)
حَدَّثَنَا أَبُو النُّعْمَانِ، حَدَّثَنَا مَهْدِيُّ بْنُ مَيْمُونٍ، سَمِعْتُ مُحَمَّدَ بْنَ سِيرِينَ، يُحَدِّثُ عَنْ مَعْبَدِ بْنِ سِيرِينَ، عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ ـ رضى الله عنه ـ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏"‏ يَخْرُجُ نَاسٌ مِنْ قِبَلِ الْمَشْرِقِ وَيَقْرَءُونَ الْقُرْآنَ لاَ يُجَاوِزُ تَرَاقِيَهُمْ، يَمْرُقُونَ مِنَ الدِّينِ كَمَا يَمْرُقُ السَّهْمُ مِنَ الرَّمِيَّةِ، ثُمَّ لاَ يَعُودُونَ فِيهِ حَتَّى يَعُودَ السَّهْمُ إِلَى فُوقِهِ ‏"‏‏.‏ قِيلَ مَا سِيمَاهُمْ‏.‏ قَالَ ‏"‏ سِيمَاهُمُ التَّحْلِيقُ ‏"‏‏.‏ أَوْ قَالَ ‏"‏ التَّسْبِيدُ ‏"‏‏.‏