A sizable number of Jedi, in training, confused the meanings of attack, defense and aggression. Thus Younglings were taught that it was possible for a Jedi to strike without aggression, so long as they acted without recklessness, hatred or anger. A Jedi was permitted to kill in self-defense—only if there was no other option. However, Jedi instructors taught their students that killing, no matter what the circumstances, was not to become commonplace. To conquer aggression, even in combat, a Jedi must have explored every other option, including surrender, before resorting to using lethal force. Jedi who depended on murder were close to the Dark Side of the Force. Jedi were expected never to commit murder, for any reason.
However, if confronted with a life-or-death struggle, a Jedi was permitted to kill to complete their mission. This act was not encouraged, as ending life strengthened the dark side; however, if the act was justified—if it saved others’ lives, or if the Jedi was acting on the will of the Force—then the light side was equally strengthened. Jedi were also expected to think of those they had killed, and to think of the suffering caused by their deaths. A Jedi who did not care about his victims was on the path to the dark side.