Chapter 33 of the Tao Te Ching

He who has enough perspicacity to know men and distinguish them one from another may be called prudent; but this is not as difficult as knowing oneself. Only he who can know his own nature deserves to be regarded as the most enlightened man in the world.

He who has enough courage to conquer men and subjugate them may be called strong; but this is not as difficult as conquering oneself. Only he who can conquer his passions deserves to be called the strongest in all the universe.

C: He who knows men is prudent; he sees external things. His knowledge is limited to knowing the good or bad qualities of men, their talents' superiority or inferiority. He who knows himself is enlightened; he has an inner vision. Only he is capable of knowing himself who concentrates his hearing to hear what has no sound (the Tao), and his sight to see what has no form (the Tao).

He who does not know when he has enough has insatiable desires; even with abundant riches, he would always be in need. Such a man cannot be called rich. Only he deserves this name who is content with himself, remains calm and free from desires, and is rich with little.

强行 qiáng xíng: “He who cannot act with vigor (to reach the Tao) often fails in his designs. His will is not worthy of mention. But the sage who acts with vigor advances constantly (toward the Tao); the more distant the Tao seems, the more his will is stirred to seek it. One can say he is endowed with firm resolve.”

This explanation would seem contrary to Lao-tseu's system if one did not remember that he only blames the use of force and vigor when applied to the pursuit of worldly things.

Every being has its particular essence. He who strays from it perishes swiftly; he who preserves it endures long. If this is true of beings, how much more so of the heart. Not straying from purity is what Lao-tseu calls 不失其所 bù shī qí suǒ, that is, 'not losing one's nature.'

This difficult passage has greatly puzzled commentators. C believes that the word 死 sǐ 'to die' refers to the death of the body, and 不亡 bù wáng 'not perishing' to the immortality of the spirit (soul). He supports this with the following passage from the work titled 丹经 Dān Jīng: 'The heart dies, but the spirit (soul) lives forever. The sensitive soul extinguishes, but the spiritual soul preserves its light.'

Nong-sse: The expressions 不化 bù huà 'not transforming' from the philosopher Lie-tseu, 不死 bù sǐ 'not dying' from the philosopher Chuang-tseu, and 不灭 bù miè 'not perishing' from the Buddhists have exactly the same meaning. The human body is like the shell of a cicada or the slough of a snake. We only make a temporary stay there. For when the cicada's skin is dried out, the cicada is not yet dead; when the snake's slough is decomposed, the snake is not yet dead.

Animal life dissipates, but the soul always remains.

Sou-tsen-yeou: Despite the great changes called life and death, his nature (the sage's nature) preserves its purity and does not perish. Thus, the perfect men of antiquity were able to escape the changes of life and death.

Li-si-tchaï: The sage views life and death like morning and evening. He exists without clinging to life; he dies without perishing. This is what is called longevity.