True words are not beautiful;
Beautiful words are not true.
A good man does not argue;
He who argues is not a good man.

(...)

To know what you do not know is the best.
To pretend to know when you do not know is a disease.
Only when one recognizes this disease as a disease can one be free from the disease.
The sage is free from the disease.
Because he recognizes this disease to be a disease, he is free from it.

(...)

My sayings are very easy to recognize,
and very easy to apply.
But no one in the world can recognize them,
and no one can apply them.

Sayings have a source,
events have a leader.
It is only through ignorance that I am not known.
Those who know me are rare;
those who emulate me are noble.

This is why sages dress plainly,
and conceal what is precious.

(Tao Te Ching)