知者不言；言者不知。
1. He who knows (the Dào) does not (care to) speak (about it); he who is (ever ready to) speak about it does not know it.
塞其兑閉其門。挫其銳解其紛；和其光，同其塵。是謂玄同。
2. He (who knows it) will keep his mouth shut and close the portals (of his nostrils). He will blunt his sharp points and unravel the complications of things; he will attemper his brightness, and bring himself into agreement with the obscurity (of others). This is called 'the Mysterious Agreement.'
故不可得而親，不可得而疏；不可得而利，不可得而害；不可得而貴，不可得而賤：故為天下貴。
3. (Such an one) cannot be treated familiarly or distantly; he is beyond all consideration of profit or injury; of nobility or meanness:—he is the noblest man under heaven.
Legge's Comments
玄德, 'The Mysterious Excellence.' The chapter gives us a picture of the man of Dào, humble and retiring, oblivious of himself and of other men, the noblest man under heaven.
Par. 1 is found in Zhuāngzǐ (XIII, 20 b), not expressly mentioned, as taken from Lǎozǐ, but at the end of a string of sentiments, ascribed to 'the Master,' some of them like the two clauses here, no doubt belonging to him, and the others, probably Zhuāngzǐ's own.
Par. 2 is all found in chapters 4 and 52, excepting the short clause in the conclusion.