Also known as the quotation from Dante's Inferno that opens T.S. Eliot's The Love Song of J. Alfred Prufrock.
[Loose translation: "If I thought you could take these words back to the world, I'd stay silent -- but no one's ever returned to earth from here (if what I hear is true), so I can speak to you without fear." Apologies for the dodgy pronounciation -- my acquaintance with spoken Italian is pretty much limited to music.]
"Let us go then..."