The art of speech consists in the following: With the intelligent speech must be based on vast learning, with the learned on dialectic, with dialecticians on equanimity(*) , with the noble on power, with the wealthy on influence, with the poor on profit, with the brave on boldness, with the stupid on demonstration. That is the art of speech. One does not succeed, if one starts before having thought the matter over ; one reaps very little, if one begins the harvest too soon.

One must not say what is not proper, nor do what is not correct to avoid danger. Nor must one take away anything, if not allowed to do so for fear of punishment, nor dispute on things which are not debatable, lest the word escape. The swiftest horse does not bring back a wrong utterance nor overtake a rash word. Therefore he is called an ideal man who never utters bad words nor listens to wicked talk.

(*) Note Forke) With an able adversary, one must never lose one’s temper, always keeping clear-headed.

Deng Xi « (c. 546 – 501 BCE) was a Chinese philosopher and rhetorician who was associated with the Chinese philosophical tradition School of Names. » (Wikipedia, Deng Xi)

Quoted after:
Forke Alfred. 1901. The Chinese Sophists. Journal of the North China Branch of the Royal Asiatic Society, XXXIV, Changai. P. 61-62.

Cité d’après http://classiques.uqac.ca/classiques/forke_alfred/the_chinese_sophists/chinese_sophists.html