Imam Ali, the son-in-law and cousin of the Prophet Muhammad, had a full democratic behavior toward and allowed complete freedom to Kharijites or Khawarij in Arabic language - a general term embracing Muslims who initially supported the authority of the Imam and Caliph Ali ibn Abi Talib and later rejected his leadership. Although Imam Ali (A.S) was the caliph and had the authority to adopt any policy he wished, he did not imprison Kharijites, did not whip them, and even did not cut their share of the public treasury, treating them like others. Such behaviour is not surprising in the lifetime of Imam Ali (A.S), but it is rare in the world. Kharijites had the absolute freedom of speech everywhere and Imam Ali (A.S) and his followers talked to them, argued, and exchanged their views.
Such freedom is almost unprecedented in the world. Kharijites went to the mosque where Imam Ali (A.S) was preaching, interrupting his sermon.
One day, when Imam Ali (A.S) was addressing people from the pulpit, a man asked a question and answered immediately. One of the Kharijites, who was among the addressees, shouted, "May God kill him. What a sage he is!" The others were going to oppose him, but Imam Ali (A.S) told them to leave him and said, "He cursed me not anybody else."
Translated by: Sadroddin Musawi
source : www.tebyan.net