Because, when an army is hard pressed, as Tu Mu says, there is always a fear of mutiny, and lavish rewards are given to keep the men in good temper.
too many punishments betray a condition of dire distress.
Because in such case discipline becomes relaxed, and unwonted severity is necessary to keep the men to their duty.
37. 先暴而後畏其衆者不精之至也
To begin by bluster, but afterwards to take fright at the enemy’s numbers, shows a supreme lack of intelligence.
I follow the interpretation of Ts‘ao Kung: 先輕敵後聞其衆則心惡之也, also adopted by Li Ch‘üan, Tu Mu and Chang Yü. Another possible meaning, set forth by Tu Yu, Chia Lin, Mei Yao-ch‘ên and Wang Hsi, is: “The general who is first tyrannical towards his men, and then in terror lest they should mutiny, etc.” This would connect the sentence with what went before about rewards and punishments. The T‘ung Tien and Yü Lan read 情 “affection” instead of 精.
38. 來委謝者欲休息也
When envoys are sent with compliments in their mouths, it is a sign that the enemy wishes for a truce.
Tu Mu says: 所以委質來謝此乃勢已窮或有他故必欲休息也 “If the enemy open friendly relations by sending hostages, it is a sign that they are anxious for an armistice, either because their strength is exhausted or for some other reason.” But it hardly needs a Sun Tzŭ to draw such an obvious inference; and although Tu Mu is supported by Mei Yao-ch‘ên and Chang Yü, I cannot think that hostages are indicated by the word 委.
39. 兵怒而相迎久而不合又不相去必謹察之