One Ring to rule them all, One Ring to find them, One Ring to bring them all and in the darkness bind them.
The words of fire etched on Frodo's golden ring reveal the Baggins' family heirloom to be the most powerful and evil object in all of Middle-earth, a physical embodiment of the worst that is thought and felt: cruelty, domination, greed. Yet the Ring's true nature normally lies hidden beneath a "quite plain" exterior, a simple band of pure gold that seems unmarked and unremarkable. As characters interact with this apparently innocuous trinket, their temptation to take and use the Ring reinscribes those fiery letters and illustrates the present, active, and dangerous power of the Ring.
The powerful, such as Gandalf and Galadriel, desire to take the Ring, but they also fear the consequences of wielding its power. When, despairing of his ability to destroy the Ring, Frodo offers it to Gandalf, the wizard immediately refuses because he recognizes the danger: "the way of the Ring to my heart is through pity, pity for weakness and the desire of strength to do good." Because the Ring is evil, the wizard knows that any attempt to wield it for good purposes will be corrupted. Galadriel admits, "For many long years I have pondered what I might do, should the Great Ring come into my hands." The power of that temptation transforms her, so that "she stood before Frodo seeming now tall beyond measurement, and beautiful beyond enduring, terrible and worshipful." Nevertheless, her wisdom aids her in conquering that desire, for she knows the defeat of Sauron cannot be achieved by taking the Dark Lord's place.
For less mighty characters, the temptation of the Ring becomes, if anything, more powerful. Although a strong and proud man, Boromir acknowledges his country's weakness at the Council of Elrond: "though I do not ask for aid, we need it." That knowledge of weakness opens him to the Ring's influence, the desire to wield it growing stronger the more he thinks of Minas Tirith's danger. At last he succumbs, "his fair and pleasant face . . . hideously changed" by madness when he attacks Frodo. Sam does take the Ring for the right reason, to keep it out of orc hands at Cirith Ungol, but again his own weakness tempts him to keep and wield the Ring — even to challenge the Dark Lord. "Wild fantasies arose in his mind; and he saw Samwise the Strong, Hero of the Age, striding with a flaming sword across the land . . . at his command the vale of Gorgoroth became a garden of flowers and trees and brought forth fruit." What saves Sam from the temptation that overpowered Boromir is his lack of worldliness and ambition. Where Boromir wants to defend his city and rule it, Sam desires only "the one small garden of a free gardener . . . not a garden swollen to a realm."
The final and greatest temptation in the novel is that of Frodo at the Cracks of Doom. From the first revelation of the fiery letters in his home at Bag End, Frodo has known that he cannot and must not wield the Ring. Twice he tries to give it away, first to Gandalf and again to Galadriel. Always he has known that it must be destroyed. Its evil will warp and corrupt everyone it contacts, as it warped and corrupted Frodo's perception of Bilbo and Sam and as it warped and corrupted Boromir. When the time finally comes, however, Frodo is also the weakest and most vulnerable he has ever been. He has been beaten and starved. He has left behind weapons and armor that he does not have the strength to bear, abandoning all his defenses. He can hardly crawl the last miles until Sam must finally carry him up the slope of the mountain. And it is there, in his weakness, that the Ring takes him: "I do not choose now to do what I came to do." Even knowing that his decision will cause the suffering of untold numbers of people, including his own companions, Frodo cannot resist the temptation to take the Ring as his own.
Put in the context of the other temptation scenes, Frodo's failure at the Cracks of Doom reveals that the danger of the Ring is not limited to its use. Wielding power — especially the immense power of the Ring — can corrupt even the most wise and well-intentioned. The more subtle danger of the Ring, however, is its ability to prey on the desires of those who are powerless. Even more than its use, the eagerness to acquire power can destroy.