Fyodor Ivanovich Tyutchev - Silentium

Speak not, lie hidden, and conceal
the way you dream, the things you feel.
Deep in your spirit let them rise
akin to stars in crystal skies
that set before the night is blurred:
delight in them and speak no word.
How can a heart expression find?
How should another know your mind?
Will he discern what quickens you?
A thought once uttered is untrue.
Dimmed is the fountainhead when stirred:
drink at the source and speak no word.
Live in your inner self alone
within your soul a world has grown,
the magic of veiled thoughts that might
be blinded by the outer light,
drowned in the noise of day, unheard...
take in their song and speak no word.

Fyodor Ivanovich Tyutchev

http://www.poemhunter.com/poem/silentium-2/