Everyone agrees that a secret should be kept intact, but everyone does not agree as to the nature and importance of secresy. Too often we consult ourselves as to what we should say, what we should leave unsaid.
 François de La Rochefoucauld, Reflections; or Sentences and Moral Maxims (1665). copy citation

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Author François de La Rochefoucauld
Source Reflections; or Sentences and Moral Maxims
Topic importance secret
Date 1665
Language English
Reference
Note Translated by J. W. Willis Bund
Weblink http://www.gutenberg.org/files/9105/9105-h/9105-h.htm

Context

“It is far safer and more honest to tell nothing than to be silent when we have begun to tell. There are other rules to be observed in matters confided to us, all are important, to all prudence and trust are essential.
Everyone agrees that a secret should be kept intact, but everyone does not agree as to the nature and importance of secresy. Too often we consult ourselves as to what we should say, what we should leave unsaid. There are few permanent secrets, and the scruple against revealing them will not last for ever.
With those friends whose truth we know we have the closest intimacy. They have always spoken unreservedly to us, we should always do the same to them.” source