"The success of the [9/11] attacks, Sheik Omar concluded, showed that 'there is no defense system could stand in the way of the determination of a person who wants to become a Martyr.' His conception of a martyr, it should be noted, differs from the common Western idea, derived from Christianity. A Christian martyr is someone who is killed for his faith, without bringing his own death upon himself. The notion of a 'martyr' as someone who kills others viewed as enemies of the faith, and in the process gets himself killed, is a distinctly Islamic concept."

-- Robert Spencer, Islam Unveiled.