Which bomb?  "The bomb" (as in Hiroshima" or the bomb dropped a few weeks ago?  Big difference.  If you find 90 members of ISIS in one place at one time and fail to kill them, you're derelict (provided you yourself are not killing an unwarranted number of innocents).  Why?  Because there is a duty to protect innocent human life against attack by a deadly unjust aggressor.  Jesus never said anything to the contrary, and in fact, supported the principle I just stated.