The fellowship of the ring are tasked with the seemingly impossible quest to destroy the One Ring of power into the fires of Mount Doom, which stands at the heart of Mordor. In order to get there, they must take many treacherous paths, including the cruel mountains of caradhras, and the long dark tunnels of the Mines of Moria.
When they get to the entrance in the 2001 film adaptation by Peter Jackson, however, they find that the door is encrypted with an elvish riddle that only Frodo can solve. So why is there an elvish inscription on the gateway to a dwarven mine?
In order to answer this question, it is important to understand the origins of Moria itself. Moria is a mining kingdom that was set up by the Durin the dwarf in the First age, because they had discovered rare and precious gems deep under the mountain, including the most coveted precious metal Mithril, like the chain mail that is gifted to Bilbo, and then passed down to Frodo. But the door itself was built by Celebrimbor, the maker of the nine rings of power that turn the kings of men into Ring-wraiths.
Celebrimbor made the door alongside Navi, a close friend and fellow smith who worked with stone and iron. Their friendship existed long before the days when elves and dwarves began to despise each other and has often been linked to the relationship between Gimli and Legolas, who came to see each other as the closest of friends during their battles against the Haradrim in Pelennor fields. Thus, in part, the door has elvish language upon it because it was crafted by an elven stone-smith.
The second reason has to do with the geography of Moria. As they stand at the entrance, Gimli recites a poem about the famous welcome of the vast halls, and in it he talks about the splendour of prosperity for all. When the rule was first established under the mountains, there was an elven settlement called Hollin nearby, on the west side of the range. The elves from Hollin were good friends of the dwarves, and often helped with the carrying of supplies and trading, as well as keeping the dwarves up to date with the comings and goings of the surrounding world.
Both elves and dwarves benefitted from the rare minerals and shared in the bounty and joy of their friendship. The gate that the fellowship enter through, after they are forced to say goodbye to Bill the pony, and go into the danger that awaits, is the gate of Hollin, which was created for the elves to have easy entrance. It is comical that in the film version, Gandalf believes the words are a challenge to keep out unwanted guests who don’t know the password, whereas the truth of it is that the words are actually a welcome to any passing elves who may have need of refuge. However, the words are written in Tengwar, an older and much less common kind of elvish than the Sindarian that Gandalf is more familiar with, hence his misinterpretation of the scripture on the gate.
When the original dwarves were given their seven rings of power, it made their greed and lust for gold even stronger, bringing out the worst traits in the race. That is why they dug too deep and awoke great evils, including the Balrog that kills Gandalf, and Smaug the dragon, who destroyed the settlement of Dale. By the time the fellowship enters Moria, it has been destroyed by evils, then reclaimed by Balin, and then destroyed again by a band of orcs wielding cave trolls in the dark. Lead at first by Gandalf’s famous flame magic, the group manages to find their way out of the dark tunnels at the other end of Moria, passing through the Dimrill Dale on their way to Lothlorien, where they can rest and recuperate, and lament the loss of their leader the Grey Wizard.
After the dark lord Sauron is defeated, and Middle Earth starts a new age of peace and prosperity under the guiding influence of Aragorn, the rightful heir to Gondor, the race of elves passes almost entirely from existence into the Undying Lands. The dwarves too, slowly die out, and the Age of Men becomes recorded in the red book of Westmarch, as one of the finest in their history. But in honor of his friendship with them, and of his essential part in destroying the ring and creating a better world for all peop[les, the elves allow Gimli to be the first-ever dwarf to sail into the west. Perhaps the strong bonds that forged the Hollin gate of Moria have not totally disappeared from Middle Earth after all.