"I said to Abu Sa'eed Khudri: 'Did you hear the Messenger of Allah mention anything about the Haruriyyah (a sect of Khawarij)?' He said: 'I heard him mention a people who would appear to be devoted worshippers: "Such that anyone of you would regard his own prayer and fasting as insignificant when compared to theirs. But they will pass through Islam like an arrow passing through its target, then he (the archer) picks up his arrow and looks at its iron head but does not see anything, then he looks at the shaft and does not see anything, then he looks at the band: that which is wrapped around the iron head where it is connected to the shaft, then he looks at the feather and is not sure whether he sees anything or not." (Using translation from Ibn Mājah 169)   

سَمِعْتُ رَسُولَ اللهِ ﷺ يَذْكُرُ فِي الْحَرُورِيَّةِ شَيْئًا؟ قَالَ سَمِعْتُهُ يَذْكُرُ قَوْمًا يَتَعَمَّقُونَ فِي الدِّينِ يَحْقِرُ أَحَدُكُمْ صَلَاتَهُ عِنْدَ صَلَاتِهِمْ وَصَوْمَهُ عِنْدَ صَوْمِهِمْ يَمْرُقُونَ مِنَ الدِّينِ كَمَا يَمْرُقُ السَّهْمُ مِنَ الرَّمِيَّةِ أَخَذَ سَهْمَهُ فَنَظَرَ فِي نَصْلِهِ فَلَمْ يَرَ شَيْئًا ثُمَّ نَظَرَ فِي رُصَافِهِ فَلَمْ يَرَ شَيْئًا ثُمَّ نَظَرَ فِي قَدَحِهِ فَلَمْ يَرَ شَيْئًا ثُمَّ نَظَرَ فِي الْقُذَذِ فَتَمَارَى هَلْ يَرَى شَيْئًا أَمْ لَا