Tao Te Ching: 56

Those who know don't talk.
Those who talk don't know.

Close your mouth,
block off your senses,
blunt your sharpness,
untie your knots,
soften your glare,
settle your dust.
This is the primal identity.

Be like the Tao.
It can't be approached or withdrawn from,
benefited or harmed,
honored or brought into disgrace.
It gives itself up continually.
That is why it endures.