Listen to this articleshīzhí-wéizhuànɡ 师直为壮
Troops Will Be Powerful When Fighting a Just Cause.
用兵有正当的理由，士气就旺盛，富有战斗力。“师”泛指军队，在此指出兵、进军征伐；“直”即正，指名义、理由正当；“壮”即壮盛，有力量。中华民族自古不轻言战争，而是注重战争的正义性，并且相信为正义而战的军队一定斗志旺盛、所向无敌。
This term suggests that when there is a good cause to use military force, the troops will be high in morale and valiant in fighting. The word shi (师) here is a general term for all military forces and operations. The word zhi (直) means a just cause. The word zhuang (壮) means powerful troops. The Chinese nation has always been wary of waging wars, believing that a war should be fought only for a just cause and that an army fighting for such a cause will have high morale and wins the war.
引例 Citation：
◎师直为壮，曲为老，岂在久乎？（《左传·僖公二十八年》）
（出兵作战，理由正当就会气壮，理由不正当就会气衰，哪里因军队长久在外呢？）
In fighting a just war, the troops will have high morale and be powerful, while they suffer from poor morale when the cause is unjust. Morale has nothing to do with how long an army is deployed at the front. (Zuo’s Commentary on The Spring and Autumn Annals)
