J. R. R. Tolkien, a devout Roman Catholic, embodied Christianity in his legendarium, including The Lord of the Rings. Light is a prominent motif in Christianity: it is the first thing created by God in the Book of Genesis, it symbolizes God's grace and blessings elsewhere in the Old Testament, and it is closely associated with both Jesus and humanity itself in the Gospel of John in the New Testament.
In The Silmarillion, light is similarly important. It appears early on in the Years of the Lamps, with two enormous lamps atop mountain-sized pillars to light the world of Arda. When these are destroyed by the Dark Lord Melkor, they are replaced by the Two Trees of Valinor, which provide light for the new home of the Valar. When these too are destroyed, the Valar use their last fruit and their last flower to create the Sun and the Moon. A little of the light of the Two Trees is captured in the Silmarils, the crafted jewels that give the book its name. These are coveted by the Dark Lord, provoking war and the destruction of much of the world of Elves, Men, and Dwarves. A survivor, Eärendil, sails across the Great Sea to ask the Valar to intervene; they expel the Dark Lord, and Eärendil and his ship Vingilot sail the heavens as the Morning Star.