It is second in authority only to the Qur'an and is often used to clarify things not specified in the Qur'an. Had I not found it difficult for my followers, then I would not remain behind any sariya going for Jihad and I would have loved to be martyred in Allah's cause and then made alive, and then martyred and then made alive, and then again martyred in His cause. Narrated Abu Huraira. Obviously Muhammad taught that Holy War was an acceptable and good thing to do. To clarify, he even stated that if a Muslim were to die in battle, fighting for the cause of Allah, that he would be guaranteed to go to Paradise.
People act according to their beliefs.
First, let me say that by far the majority of Muslims I have encountered here in the United States have been polite and peace loving. Second, in other parts of the world, Jihad is taken to extremes not simply by terrorists, but by Islamic led governments. In Egypt, a Muslim country, Christians have been persecuted heavily for their faith and only recently are things beginning to change. And Naguib Mahfouz, the elderly and much-celebrated Nobel Prize laureate for literature, was seriously injured in Cairo when an assailant knifed him in the neck, presumably in revenge for an allegorical novel written decades earlier. This Christmas season, Pastor Rod Parsley is taking a lead in an effort to help free the tens of thousands of Sudanese women and children held in captivity in the Sudan, many of which are Christians.