[Elladan and Elrohir]

"The Lord of the Rings is a fundamentally religious and Catholic work. Unconsciously so in the writing, but consciously in the revision." - J.R.R. Tolkien

Although Tolkien "detest[ed] allegory in all its forms" (Prologue, The Lord of the Rings), he had a very definitely Christian worldview, and that shines through in all his writings. Obviously, The Silmarillion is very Christian in its account of the creation of Arda by Eru Iluvatar, and the fall of Melkor.

There are in fact three of what you might call Christ figures in The Lord of the Rings, though none of them present a complete picture of Jesus: each prominently display a different quality.

First, and first noticed on this thread, is Frodo. He is a Christ figure in the sense that he sacrifices everything he has and is to save his beloved Shire, and also Middle-earth. His torturous bearing of the Ring is very similar to Jesus taking the sins of mankind upon Himself. Obviously Frodo is incomplete in that he fails in the end and his Quest is only allowed to succeed through divine grace.

Second, there is Gandalf. Gandalf also makes a sacrifice on a slightly smaller scale: sacrifices himself to preserve the Quest and the lives of the rest of the Company in Moria. He is rewarded for this sacrifice by being allowed to return, in greatly enhanced power. It doesn't take a rocket scientist to see that the main similarities between Gandalf and Jesus are their perfection, their sacrifice, and ultimately, resurrection. However, Gandalf is also incomplete: obviously, he is not God Himself, and like Frodo, depends on God's grace to vindicate him.

Finally, there is Aragorn. In Aragorn we see the kingly nature of Jesus, the promised Messiah of the Jews. Aragorn and Jesus are both descended in a right line from famous and powerful kings. Yet both hide their glory and majesty -- for a little while. They each have a job to do on Earth, albeit that the jobs are completely different ones. Obviously, Aragorn is also an incomplete Christ figure because, unlike Gandalf and Frodo, he makes no real sacrifice (other than waiting all those years to marry Arwen, and this is inconsequential). He is obviously not perfect.

So, in Frodo we see Jesus' sacrifice, in Gandalf we see His Resurrection, and in Aragorn we see Him as the King of Kings.

I'm not suggesting that Tolkien intentionally put Christ-like characteristics in these three main characters in LOTR, but it is certainly intriguing, especially for someone who is a Christian like he was, and like I am. Whether Tolkien intended it or not, these three main characters each point us, in different ways, to Jesus Christ.