The chapter opens with the line most often quoted from this book after the first sentence of chapter one, and most often quoted against it. One who knows does not speak, and one who speaks does not know.
The obvious objection is that the sentence is itself speech in a book of five thousand characters, and readers have been making it for as long as the text has circulated. The objection is not fatal but it is not trivial either, and the book has no single answer to it. Chapter two recommends teaching without words. Chapter forty-three says such teaching is matched by few in the world. Chapter seventy admits that the words are easy and that nobody understands them. Chapter eighty-one opens by saying that trustworthy words are not fine.
What the chapter itself claims is narrower than the general paradox suggests. The verb is closer to holding forth than to speaking at all, and the target throughout the book is assertion, display and the setting up of positions, which is the same fault chapters twenty-two and twenty-four attack in the person who considers himself right.
The rest of the chapter is a set of instructions, four of which appear again elsewhere. Block the openings and shut the gates, which chapter fifty-two also gives. Blunt the sharpness, untie the tangles, soften the glare, settle with the dust, which chapter four applies to the way itself.
That reuse is worth noticing. The four clauses describe the way in chapter four and a person here, and the book makes that transfer without comment, which is as close as it comes to saying what the practice is for.