Another quote from The Narnian by Alan Jacobs, page 314. These are C S Lewis's words. They were read at Kenneth Tynan's funeral.
The books or the music in which we thought the beauty was located will betray us if we trust to them; it was not in them, it only came through them, and what came through them was longing. These things - the beauty, the memory of our own past - are good images of what we really desire; but if they are mistaken for the thing itself, they turn into dumb idols, breaking the hearts of their worshippers. For they are not the thing itself; they are only the scent of a flower we have not found, the echo of a tune we have not heard; news from a country we have never yet visited.
At risk of adding to Lewis's excellent words, this should encourage us that what we write is always more than we know.