The ancient masters were subtle, mysterious, profound, responsive.
The depth of their knowledge is unfathomable.
Because it is unfathomable,
All we can do is describe their appearance.
Watchful, like men crossing a winter stream.
Alert, like men aware of danger.
Courteous, like visiting guests.
Yielding, like ice about to melt.
Simple, like uncarved blocks of wood.
Hollow, like caves.
Opaque, like muddy pools.
Who can wait quietly while the mud settles?
Who can remain still until the moment of action?
Observers of the Tao do not seek fulfilment.
Not seeking fulfilment, they are not swayed by desire for change.
 The Ma wang tui text has these two lines in reverse order, but both it and all the others I have read the line Feng translated as 'Hollow, like caves' as something more like 'Broad and expansive, like a valley'.
 The Ma wang tui text does not read this as a question. It has:
If you take muddy water and still it, it gradually clears.
If you bring something to rest in order to move it, it gradually comes alive.
 Most other texts have the idea that, not seeking to become full, they were never in need of renewal.
This is a rather intriguing chapter, particularly when compared with the description in ch.22 where the 'Man of Tao' is described as much 'softer-edged'.