The Kharijites were individuals who as a result of their fanaticism and extremism, had gone greatly astray. Their leader was a person by the name of Hurqus Ibn Zuhair, who, during the time of the Noble Prophet (s.a.w), had drowned himself in prayers, fasts and other acts of worship causing many of the Muslims to become fascinated with him.
When the Noble Prophet (s.a.w) had been distributing the spoils of war after the battle of Hunain, this person, who was just an arid and ceremonial worshipper, said to him with great impudence: “O’ Muhammad! Conduct yourself with fairness and equality,” and repeated the sentence three times. When he had repeated it for the third time the Noble Prophet (s.a.w) became greatly disturbed and said: “If I do not behave with fairness and equality, then who shall behave so?”
This ‘dry’ worshipper eventually set out for battle against Imam ‘Ali (a.s) in the battle of Nahrawan and was killed. When the Imam’s (a.s) eyes fell upon his inauspicious corpse lying amongst the dead, he (a.s) offered a prostration of thanksgiving and said (to his companions): “You have killed the worst of the men.” ( Dastan-ha Wa Pand-ha, vol. 9, pg. 77; ‘Ali Wa Farzandan (Dr. Taha Husain), pg. 123 )