Henry Wadsworth Longfellow said this quote
“ O, how wonderful is the human voice! It is indeed the organ of the soul! The intellect of man sits enthroned visibly upon his forehead and in his eye; and the heart of man is written upon his countenance. But the soul reveals itself in the voice only; as God revealed himself to the prophet of old in the still, small voice; and in a voice from the burning bush. The soul of man is audible, not visible. A sound alone betrays the flowing of the eternal fountain, invisible to man! ”