夫佳兵者,不祥之器,物或惡之,故有道者不處。
君子居則貴左,用兵則貴右。
兵者不祥之器,非君子之器,不得已而用之,恬淡為上。
勝而不美,而美之者,是樂殺人。夫樂殺人者,則不可以得志於天下矣。

吉事尚左,凶事尚右。
偏將軍居左,上將軍居右,言以喪禮處之。
殺人之衆,以哀悲泣之,戰勝以喪禮處之。

Of all things, soldiers are instruments of evil,
hated by men.
Therefore the religious man (possessed of Tao) avoids them.
The gentleman favors the left in civilian life,
But on military occasions favors the right.

Soldiers are weapons of evil.
They are not the weapons of gentlemen.
When the use of soldiers cannot be helped,
The best policy is calm restraint.

Even in victory, there is no beauty,
And who calls it beautiful
Is one who delights in slaughter.
He who delights in slaughter
Will not succeed in his ambition to rule the world.

The things of good omen favor the left.
The things of ill omen favor the right.
The lieutenant-general stands on the left,
The general stands on the right.
That is to say; it is celebrated as a Funeral Rite.

The slaying of multitudes should be mourned with sorrow.
A victory should be celebrated with the Funeral Rite.
(Translation by Lin Yutang )

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This chapter is the continuation of chapter 30. Lao Tzu did tell us that he did not like a war in the previous chapter. Here he says to us not to have too much joy if we won the battle. His view is somewhat different from ordinary people.

Most people think that winning victories is a celebration of the occasion. They will lift the country joyfully on their merits and deeds. However, Lao Tzu held the opposite view. He considered winning victories joyless, and those who praised the victorious warriors, those like to kill. Anyone who likes to kill people cannot win the world. The triumph of the war in his eyes is not for celebrating, but to be treated as a funeral.

Granted, Lao Tzu was born 2500 years ago during the Warring States period, and he had seen the tragedies of a defeated country being divided up, annexed, and ruled, and the people lived in hot water. Lao Tzu is benevolent and a benefactor. Knowing and seeing the war being brutal, merciless and making the people suffered, he can not help but oppose the war.