‘He felt better at once,’ said Gandalf. ‘But there is only one Power in this world that knows all about the Rings and their effects; and as far as I know there is no Power in the world that knows all about hobbits. Among the Wise I am the only one that goes in for hobbit-lore: an obscure branch of knowledge, but full of surprises. Soft as butter they can be, and yet sometimes as tough as old tree-roots. I think it likely that some would resist the Rings far longer than most of the Wise would believe. I don’t think you need worry about Bilbo.

Book 1, Chapter 1 A Long-expected Party