Sahih Bukhari Volume 9, Book 88, Hadith 6936

حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ، حَدَّثَنَا عَبْدُ الْوَاحِدِ، حَدَّثَنَا الشَّيْبَانِيُّ، حَدَّثَنَا يُسَيْرُ بْنُ عَمْرٍو، قَالَ قُلْتُ لِسَهْلِ بْنِ حُنَيْفٍ هَلْ سَمِعْتَ النَّبِيَّ صلى الله عليه وسلم يَقُولُ فِي الْخَوَارِجِ شَيْئًا قَالَ سَمِعْتُهُ يَقُولُ ـ وَأَهْوَى بِيَدِهِ قِبَلَ الْعِرَاقِ ـ ‏"‏ يَخْرُجُ مِنْهُ قَوْمٌ يَقْرَءُونَ الْقُرْآنَ لاَ يُجَاوِزُ تَرَاقِيَهُمْ، يَمْرُقُونَ مِنَ الإِسْلاَمِ مُرُوقَ السَّهْمِ مِنَ الرَّمِيَّةِ ‏"‏‏

Narrated By Yusair bin 'Amr : I asked Sahl bin Hunaif, "Did you hear the Prophet saying anything about Al-Khawarij?" He said, "I heard him saying while pointing his hand towards Iraq. "There will appear in it (i.e. Iraq) some people who will recite the Qur'an but it will not go beyond their throats, and they will go out from (leave) Islam as an arrow darts through the game's body.'"