Have ye not known? have ye not heard? hath it not been told you from the beginning? have ye not understood from the foundations of the earth?

-Bible (Old Testament)
Isaiah 40:21.

If you would be known, and not know, vegetate in a village; if you would know, and not be known, live in a city.

-Colton, Charles Caleb
  Lacon, vol.1, no.334.

For I have known them all already, known them allö Have known the evenings, mornings, afternoons, I have measured out my life with coffee spoons; I know the voices dying with a dying fall Beneath the music from a farther room.

-Eliot,T(homas) S(tearns)
  'The Love Song of  J  Alfred Prufrock' (first published in Poetry magazine, collected in Prufrock and Other Observations, 1917).

I can scarcely fancy myself to ask a superior to publish a volume of my verse and I own that humanly there is very little likelihood of that ever coming to pass. And to be sure if I chose to look at things on one side and not the other I could of course regret this bitterly. But there is more peace and it isthe holier lot to be unknown than to be known.

-Gerard Manley Hopkins
Letter to Richard Watson Dixon, 29 Oct. Collected in C C Abbott (ed)  The Correspondence of Gerard Manley Hopkins and Richard Watson Dixon (1935).

Canada only needs to be known in order to be great.

-Hopkins,J Castell
The Story of the Dominion, preface.

Is not a Patron, my lord, one who looks with unconcern ona manstruggling for life inthewater, and,whenhehas reached ground, encumbers him with help? The notice which you have been pleased to take of my labours, had it been early, had been kind; but it has been delayed till I am indifferent, and cannot enjoy it; till I am solitary, and cannot impart it; till I am known, and do not want it.

-Johnson, Samuel known as Dr Johnson
  Letter to Lord Chesterfield,7 Feb. Quoted in  James Boswell The Life of Samuel Johnson (1791), vol.1.

   There is a lurking fear that some things are not meant 'to be known', that some inquiries are too dangerous for human beings to make.

-Sagan, Carl Edward
  Broca's Brain.

   He must have known me had heseen meashe was wont to see me, for he was in the habit of flogging me constantly. Perhaps he did not recognize me by my face.

-Trollope, Anthony
  Autobiography, ch.1.