Note: It's March 25 which is the day that the Ring of Power was cast into Mount Doom in JRR Tolkien's The Lord of the Rings. About 10 years ago, a group of Tolkien fans decided to commemorate the day by making every March 25 Read Tolkien Day. So you should go do that.
If you've not read The Hobbit or The Lord of the Rings, I can think of no better day to start (and no better time to be reading them than the days of spring and Ascension which is only a week and a half away). If you've read those, go pick up The Silmarillion. It's a denser book, but the stories are marvelous and they'll bring you a bit deeper into the imagination of Tolkien, who had a quite remarkable intellect and was a deeply formed Christian.
There's a scene near the end of The Lord of the Rings when Frodo and Sam are on the slopes of Mt Doom making their ascent to the crack in the mountain into which they hope to cast the Ring of Power, thereby bringing an end to Sauron's power in Middle Earth. But at this point it seems as if they may not make it. They've marched for weeks on weeks with little food or water. They've been attacked by giant spiders, taken captive by orcs multiple times, and now appear to have lost their final reserves of energy as they attempt to make the final push up the mountain. But something is able to keep them going--memory.
Though the exact scene isn't in the book--the reference to remembering the Shire comes earlier when Sam first saves Frodo from the orcs' tower--the spirit of this scene is deeply at home in Tolkien's story:
https://www.youtube.com/watch?v=BKIgv8AhffA
There are three things that ultimately allow Sam and Frodo to achieve their quest--none of which are intrinsic to them or somehow reflective of some hidden quality they possess in themselves. The first is memory. Even when Frodo cannot, Sam is able to call his friend back to a world they once belonged to and in that world they can find the strength to press on though they are now far from it.
This implies a second thing that drives them--which is love. The reason the memory is so potent is that it contains in it so much that they love in the world. And these are not grandiose things--they are simple things, the place they once lived in, the coming of a new season, the planting of crops, and the savoring of strawberries and cream. Pippin and Merry have a similar scene as they share a bit of pipeweed from the South Farthing with Gimli, Aragorn, and Legolas after the Battle of Helm's Deep.
There's something deeply incongruous about all this, of course. Here are two small hobbits on the slopes of Mt Doom talking about sowing barley and hearing birds in the trees. There's an important lesson here, however, and Tolkien very much wants us to see it, I think: the love of small things can sustain us in the face of great evil.
There's one last thing that allows them to fulfill their quest, of course--and that is unexpected grace. When it comes to the point, Frodo won't cast the ring into the fire and Sam can't force him to. It is only the unexpected presence of Gollum that allows them to complete the quest. Gollum, of course, is only there because first Bilbo and then Frodo chose to show mercy when they might justly have chosen retribution.
None of this, of course, is to say that the story is somehow Christian allegory or some such. Tolkien always reacted strongly when anyone attempted to find any allegorical meaning in his books, Christian or otherwise. (Some readers have tried to treat the book as somehow being about World War II.) What it does say, however, is that these books were written by a man whose heart, mind, and imagination have been deeply shaped and transformed by the Gospel. And while that isn't the only reason to read the books--the sheer pleasure of them should be sufficient--it is one reason to read them.