The Fellowship of the Ring
[T]he old man was Gandalf the Wizard, whose fame in the Shire was due mainly to his skill with fires, smokes, and lights. His real business was far more difficult and dangerous, but the Shire-folk knew nothing about it. To them he was just one of the 'attractions' at the Party. Hence the excitement of the Hobbit-children. 'G for Grand!' they shouted, and the old man smiled. They knew him by sight though he only appeared in Hobbiton occasionally and never stopped long; but neither they nor any but the oldest of their elders had seen one of his fireworks displays - they now belonged to the legendary past. (1.1.27)
"A mortal, Frodo, who keeps one of the Great Rings, does not die, but he does not grow or obtain more life, he merely continues, until at last every minute is a weariness. And if he often uses the Ring to make himself invisible, he fades: he becomes in the end invisible permanently, and walks in the twilight under the eye of the dark power that rules the Rings. Yes, sooner or later – later, if he is strong or well-meaning to begin with, but neither strength nor good purpose will last – sooner or later the dark power will devour him." (1.2.43)
"Fair lady Goldberry!" [Frodo] said again. "Now the joy that was hidden in the songs we heard are made plain to me.
O slender as a willow-wand! O clearer than clear water!
O reed by the living pool! Fair River-daughter!
O spring-time and summer-time, and spring again after!
O wind on the waterfall, and the leaves' laughter!
Suddenly he stopped and stammered, overcome with surprise to hear himself saying such things. But Goldberry laughed.
"Welcome!" she said. "I had not heard that folk of the Shire were so sweet-tongued. But I see you are an Elf-friend; the light in your eyes and the ring in your voice tells it." (1.7.5-6)