Who said "Those who know don't talk. Those who talk don't know."?

Lao Tzu (6th century BC). Source: Tao Te Ching 56.

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

Lao Tzu, Tao Te Ching 56

The source

"Those who know don't talk. Those who talk don't know." Lao Tzu said it in Tao Te Ching 56. Translated from the original Chinese by Spartan Surfers.

"知者不言，言者不知。"

Original Chinese, Tao Te Ching 56. Chinese: Wang Bi edition via zh.wikisource.

Who said it

Lao Tzu (6th century BC). Keeper of the archives at the Zhou court, by tradition the author of the Tao Te Ching: eighty-one short chapters on water, softness and knowing when to stop.

Questions

Who said "Those who know don't talk. Those who talk don't know."?: Lao Tzu (6th century BC). Source: Tao Te Ching 56.
What is the original Chinese?: 知者不言，言者不知。. Translated from the original Chinese by Spartan Surfers.