The true spirit of conversation consists more in bringing out the cleverness of others than in showing a great deal of it yourself.

[L’esprit de la conversation consiste bien moins à en montrer beaucoup qu’à en faire trouver aux autres.]

Jean de La Bruyère (1645-1696) French essayist, moralist

The Characters [Les Caractères], ch. 5 “Of Society and Conversation [De la Société et de la Conversation],” § 16 (5.16) (1688) [tr. Van Laun (1885)]
    (Source)

(Source (French)). Alternate translations:

The Wit of conversation consists more in finding it in others than shewing a great deal your self.
[Bullord ed. (1696)]

The Wit of Conversation consists more in finding it in others, than in shewing a great deal your self.
[Curll ed. (1713)]

Conversation-Wit consists more in pointing out that of others, than in shewing a great deal yourself.
[Browne ed. (1752)]

The art of conversation consists far less in displaying much wit oneself than in helping others to be witty.
[tr. Stewart (1970)]