Tao Te Ching · Chapter 70

吾言甚易知，甚易行。天下莫能知，莫能行。
言有宗，事有君。
夫唯無知，是以不我知。
知我者希，則我者貴。
是以聖人被褐懷玉。

My words are very easy to know, and very easy to practise; but
there is no one in the world who is able to know and able to practise
them.

There is an originating and all-comprehending (principle) in my
words, and an authoritative law for the things (which I enforce). It
is because they do not know these, that men do not know me.

They who know me are few, and I am on that account (the more) to be
prized. It is thus that the sage wears (a poor garb of) hair cloth,
while he carries his (signet of) jade in his bosom.