Hadith
حَدَّثَنَا بَكْرُ بْنُ خَلَفٍ أَبُو بِشْرٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، عَنْ مَعْمَرٍ، عَنْ قَتَادَةَ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " يَخْرُجُ قَوْمٌ فِي آخِرِ الزَّمَانِ - أَوْ فِي هَذِهِ الأُمَّةِ - يَقْرَءُونَ الْقُرْآنَ لاَ يُجَاوِزُ تَرَاقِيَهُمْ - أَوْ حُلْقُومَهُمْ سِيمَاهُمُ التَّحْلِيقُ إِذَا رَأَيْتُمُوهُمْ - أَوْ إِذَا لَقِيتُمُوهُمْ - فَاقْتُلُوهُمْ " .
It was narrated that Anas bin Malik said:"The Messenger of Allah said: 'At the end of time or among this nation (Ummah) there will appear people who will recite the Qur'an but it will not go any deeper than their collarbones or their throats. Their distinguishing feature will be their shaved heads. If you see them, or meet them, then kill them
Sahih · Al-Albani
Sunan Ibn Majah 175·Also available on sunnah.com·