■ Did Muhammad practice violence?
Muhammad is responsible for killing more than 500 Jews. Muhammad besieged the Banu Qurayza for 25 days until they surrendered. One of Muhammad's companions decided that "the men should be killed, the property divided, and the women and children taken as captives". Muhammad approved of the ruling. That makes Muhammad responsible for beheading more than 500 men who were not guilty and not a thread for Muhammad .
Muhammad commanded palm cutting of the enemies without justification. The Jews told him that it was forbidden according the Law of Moses (Deuteronomy 20:19). Also the Arabs and even the Muslims told him that it was forbidden according to traditional Arab practices. When the Muslims asked about the responsibility of Muhammad he said it was as divine command (Qur'an 59:5). According to the Law of Moses and the people in those days it is a violent action.
Muhammad initiated violence against the Meccan caravans (Qur'an 22:29). The raids to the Meccan caravans were offensive and carried out to gather intelligence or seize the trade goods of caravans financed by the Quraysh .
Muhammad believed that war is an evil, but that it is more important that Islam will survive. According to Muhammad, the destruction of Islam is a greater evil than war (Qur'an 2:217). Peace is not preferred, but war, until Islam is secure . Muhammad teaches to be positive about war (Qur'an 2:215).. Therefore Muhammad was initiating violence. The example of Muhammad had been used by Islam to spread this religion with violence and some Muslims are still using his example today to initiate violence .
Conclusion: Muhammad did practice violence.
 Wikipedia, Invasion of Banu Qurayza, http://en.wikipedia.org/wiki/Invasion_of_Banu_Qurayza.
 Montgomery Watt, William, Muhammad: prophet and statesman. Oxford University Press, 1974, 105.
 Kenneth Cragg, The Call of the Minaret, Oneworld Publications, 2003, 77.
 Jonathan E. Brockopp, Jihad and Islamic history, in: Bryan Rennie and Philip .L.Tite (Ed), Religion, Terror and Violence, Religious Studies Perspectives, Routledge, New York, 2008, 151.
 Robert Spencer, Islam Unveiled. Disturbing questions about The World's Fastest-Growing Faith, Encounter Books, San Francisco, 2002, 168.