My first impression was that providence, or destiny, or divine guidance, is an important part of this book. Here's a statement by Gandalf: 'Behind that there was something else at work, beyond any design of the Ring-maker. I can put it no plainer than by saying that Bilbo was meant to find the Ring, and not by its maker. In which case you also were meant to have it. . . .' (p. 65 -- the book I am using is J. R. R. Tolkien, The Fellowship of the Ring: Being the First Part of The Lord of the Rings. Boston: Houghton Mifflin Company, 1963. The book uses single quote marks, and I am quoting them, too.)
And: 'Such questions cannot be answered,' said Gandalf. 'You may be sure that it was not for any merit that others do not possess: nor for power or wisdom, at any rate. But you have been chosen, and you must therefore use such strength and heart and wits as you have.' (to Frodo, again about the fact that Frodo has found himself in possession of the Ring, left him by his uncle Bilbo, p. 70)
On page 94, the elf, Gildor Inglorion, tells Frodo that his group of elves has not met Frodo by chance. On page 137, Tom Bombadil tells Frodo much the same thing. Gildor and his elves seem to have scared the Black Riders away from Frodo and his companions, and Bombadil rescued them from Old Man Willow. On page 255, Elrond tells those who have come to Rivendell with Frodo, and the others who are there, including Boromir, Gimli and Legolas, that they are not there by accident. On page 423, Frodo tells Sam that the two of them are "meant to go together" in carrying the ring on. In no case, in the entire trilogy, is the nature of the guidance specified, but Tolkien clearly wants us to know that it is there. (There is an on-line Encyclopedia of Arda, which has hundreds of entries on characters and aspects of Tolkien's work. I have not linked to individual entries, except for this sample -- Gildor Inglorion.)
The most important passage in the entire trilogy is this:
Besides the matter of providence, three other aspects of Fellowship should be mentioned. One of them is the matter of choice. As quoted immediately above, Frodo chooses to take the Ring. But this is not the only important choice made by characters. Sam, Pippin and Merry choose to go with Frodo. Bilbo chooses to give the Ring to Frodo, although he needs help in doing this. Elrond, Gandalf, and Aragorn choose not to take the Ring. Most notably, Galadriel also chooses not to do so. (See a quotation of her speech, in this post. That speech is repeated, almost verbatim, in Peter Jackson's movie based on this book.)
A second aspect is the matter of time, in Lothlórien, and for the Elves. The Elves are immortal, and many of them, such as Galadriel, have lived for thousands of years. But time seems to run differently in their realms than in the realms outside of their most important influence.
The book, A Question of Time: J. R. R. Tolkien's Road to Faërie, Kent, Ohio: Kent State University Press, 1997, by Verlyn Flieger, deals with the importance of time to Tolkien's narrative. Part of Tolkien's use of time is as a way of escape. This is clearest in the episode in Lórien:
" . . . Frodo felt that he was in a timeless land that did not fade or change or fall into forgetfulness. When he had gone and passed again into the outer world, still Frodo the wanderer from the Shire would walk there . . ." (pp. 365-6)
The third aspect, and I hate to do this, is to question the presence of Tom Bombadil in the book. I'm not sure that he was needed. Jackson's movie ignores him, and that episode.
It was a joy to re-read this book. It is readable, and at times inspiring. Thanks for reading.