A single line can never capture the grand sweep of Tolkien’s genius. Here is a passage that really hit me hard when I first read it many many years ago.
Frodo is wearing the Ring he had put on to flee from Boromir and is sitting on the Seat of Seeing on Amon Hen. He sees afar the forces of the Dark Lord growing and is frightened.
Then turning south again he beheld Minas Tirith. Far away it seemed, and beautiful: white-walled, many-towered, proud and fair upon its mountain-seat; its battlements glittered with steel, and its turrets were bright with many banners. Hope leaped in his heart. But against Minas Tirith was set another fortress, greater and more strong. Thither, eastward, unwilling his eye was drawn. It passed the ruined bridges of Osgiliath, the grinning gates of Minas Morgul, and the haunted Mountains, and it looked upon Gorgoroth, the valley of terror in the Land of Mordor. Darkness lay there under the Sun. Fire glowed amid the smoke. Mount Doom was burning, and a great reek rising. Then at last his gaze was held: wall upon wall, battlement upon battlement, black, immeasurably strong, mountain of iron, gate of steel, tower of adamant, he saw it: Barad-dûr, Fortress of Sauron. All hope left him. And suddenly he felt the Eye. There was an eye in the Dark Tower that did not sleep. He knew that it had become aware of his gaze. A fierce eager will was there. It leaped towards him; almost like a finger he felt it, searching for him. Very soon it would nail him down, know just exactly where he was. Amon Lhaw it touched. It glanced upon Tol Brandir – he threw himself from the seat, crouching, covering his head with his grey hood. He heard himself crying out: Never, never! Or was it: Verily I come, I come to you? He could not tell. Then as a flash from some other point of power there came to his mind another thought: Take it off! Take it off! Fool, take it off! Take off the Ring! The two powers strove in him. For a moment, perfectly balanced between their piercing points, he writhed, tormented. Suddenly he was aware of himself again, Frodo, neither the Voice nor the Eye: free to choose, and with one remaining instant in which to do so. He took the Ring off his finger. He was kneeling in clear sunlight before the high seat. A black shadow seemed to pass like an arm above him; it missed Amon Hen and groped out west, and faded. Then all the sky was clean and blue and birds sang in every tree.