François de La Rochefoucauld Quote

We should observe the place, the occasion, the temper in which we find the person who listens to us, for if there is much art in speaking to the purpose, there is no less in knowing when to be silent. There is an eloquent silence which serves to approve or to condemn, there is a silence of discretion and of respect. In a word, there is a tone, an air, a manner, which renders everything in conversation agreeable or disagreeable, refined or vulgar.

Reflections on Various Subjects (1665–1678)