A ruler cannot mobilize his armies in a rage; a commander cannot incite a battle in the heat of the moment. Move if it is to your advantage; bide your time if it is not. A person in a fit of rage can be restored to good humor and a person in the heat of passion can be restored to good cheer, but a state that has perished cannot be revived, and the dead cannot be brought back to life. Thus the farsighted ruler approaches battle with prudence, and the good commander moves with caution. This is the way to keep the state secure and to preserve the army intact.