tao teh ching 43

The softest thing in the universe
Overcomes the hardest thing in the universe.
That without substance can enter where there is no room.
Hence I know the value of no-action.

Teaching without words and work without doing
Are understood by very few.

Both Lau and the Ma wang tui text agree with this in substance, although Lau groups the six lines slightly differently (3 and 3) and reads the third line of the first group as a continuation of the other two, '... That which is without substance entering, etc.'. Both use the term 'ride rough shod over' rather than 'overcome', while both Wang (as read by Lynn) and Cheng interpret this as 'galloping through' or 'controlling a galloping steed'. I think this interpretation is a touch too literal, though.

Wang Pi says:

There is no place that air cannot enter, no place that water cannot flow through.
Emptiness is so soft and pliable that there is no place it cannot penetrate, for that which has no physical existence is inexhaustible and the perfectly soft is unbreakable. It is by pursuing this line of thought that we come to understand the advantage of acting without conscious purpose (wu wei).

And Cheng: Water and wind are among the softest things in the world, but when their force is concentrated, it is enough to topple mountains and overturn the sea... In its minutest form, softness allows the insubstantial to penetrate where there is no opening. The wind erodes copper and dripping water bores through stone in just this way. Extending this description, we can include ch'i with its ability to penetrate and moisten everywhere. These are all examples of natural phenomena and if one holds to this precept one will naturally discover just how true it is. This, then, is the benefit of non-action just as it is of the wordless teaching, but few in the world can attain it.

Interestingly, we are discussing teh here - the manifest energy and power - and yet it is consistently the emptiness and open-endedness of tao that is being emphasised. Things come into and pass out of being as the day decides, but the tao of them is endless (this, of course, is the very basis of the I Ching, expressed as such, even, in hexagrams such as 32, Hêng, 'Duration'). And, as we have seen, the tao is endless only in that it does not exist as anything at all; the moment it does, that is not the tao. Tao as such is formless, nameless, and - in fact - utterly inconceivable, and yet here we see again that it precisely this that incarnates in and enlivens the 'becoming'.
And it does so, without the least fuss, instant by instant... The arising is seamless and perfectly continuous. Everything is always happening. And yet it is only the nothingness becoming. It's stunning. It's so extraordinary and yet we take it for 'only this', 'just another that'... Our vision is 'privative': we steal value from what appears before us and turn it into 'the ordinary', the dull and the grey, the already seen, already allotted... Yet even this is nothing but another sacred manifestation of the infinite display... It has no preferences. If we want it grey, it's quite happy to be grey.
It's up to us.

The wordless teaching.