Chapter 43 of the Tao Te Ching

天tiān下xià之zhī至zhì柔róu， 驰chí骋chěng天tiān下xià之zhī至zhì坚jiān。
无wú有yǒu入rù于yú无wú闻wén。
是shì以yǐ知zhī无wú为wéi有yǒu益yì。
不bù言yán之zhī教jiào，无wú为wéi之zhī益yì，天tiān下xià希xī及jí之zhī。

水 shuǐ is extremely soft, yet it can wear down mountains and hills.

无有 wúyǒu (the non-being), that is, the 道 Dào. The 道 Dào has no form; that is why it can penetrate spirits and all beings.

苏轼 Sū Shì thinks that the expression non-being refers to spirits. 刘克福 Liú Kèfú relates it to 气 qì, the ether, which he sees as immaterial, 无质 wú zhì.

The expression 无间 wújiàn means "that which has no gaps" (the impenetrable). There is no body more delicate than dust, and yet it cannot enter a body without gaps. But the being of ineffable subtlety passes through the autumn down and still has room to spare; it penetrates the hardest stones and metals without difficulty.

The Sage does not speak, and the people transform themselves; he practices non-action, and affairs are well managed. This is how his complete sincerity naturally accomplishes great meritorious deeds. But other men need to issue instructions to be obeyed; they need to act to succeed in their plans. They expend much effort and achieve only meager results. They are far from the path of the Sage!

严君平 Yán Jūn Píng says: He who acts in a forceful manner may fail and lose the merit he aspires to; he who acts without acting achieves boundless success. This is how heaven and earth operate; this is how men and beings arise.

The voice that expresses itself in sound is heard only up to a hundred li; the voice that is devoid of sound reaches beyond the sky and shakes the whole empire.

Human words are not understood by different kinds of men; but, at the word of the being that does not speak, the 阴 Yīn and the 阳 Yáng (the female and male principles) spread their fertile influences, heaven and earth unite to produce beings. Now, the 道 Dào and Virtue do not act, and yet heaven and earth give full growth to creatures. Heaven and earth do not speak, and yet the four seasons follow their course. This is how I see that non-action is beneficial to men.

Literally: "The teaching of non-speaking, the usefulness of non-action, in the world few men attain this."

Men do not know how to teach others because they speak. Then they rely on their prudence, pride themselves, boast, and love to act. He who loves to act is easy to overthrow. From this, one sees that teachings accompanied by words, conduct that manifests through action, are useless things. Hence, in the world, there are few men who can teach without using words and reap the benefits of non-action.