The Fellowship of the Ring
"[The poem] came to me then, as if I was making it up; but I may have heard it long ago. Certainly it reminds me very much of Bilbo in the last years, before he went away. He used often to say there was only one Road; that it was like a great river: its springs were at every doorstep, and and every path was its tributary. 'It's a dangerous business, Frodo, going out of your door,' he used to say. 'You step into the Road, and if you don't keep your feet, there is no knowing where you might be swept off to. Do you realize that this is the very path that goes through Mirkwood, and that if you let it, it might take you to the Lonely Mountains or even further and to worse places?' He used to say that on the path outside the front door at Bag End, especially after he had been out for a long walk." (1.3.74)
"You have read his book!" cried Frodo. "Good heavens above! Is nothing safe?"
"Not too safe, I should say," said Merry. "But I have only had one rapid glance, and that was difficult to get. He never left the book about. I wonder what became of it. I should like another look [...] I kept my knowledge to myself, till this Spring when things got serious. Then we formed our conspiracy; and as we were serious, too, and meant business, we have not been too scrupulous. You are not a very easy nut to crack, and Gandalf is worse. But if you want to be introduced to our chief investigator, I can produce him." (1.5.63-4)
Sam sat down and scratched his head and yawned like a cavern. He was worried. This afternoon was getting late, and he thought this sudden sleepiness uncanny. "There's more behind this than sun and warm air," he muttered to himself. "I don't like this great big tree. I don't trust it. Hark at it singing about sleep now! This won't do at all!" (1.6.52)