Speaking about the Christian motives, there is one of lesser importance, even though worth mentioning. It is the allusion to Paradise which is in The Silmarillion represented by Valinor, a holy land where the Valar lived. It was actually a continent that lay westward from the Middle-earth. Likewise the biblical Paradise, Eden, it is described as a beautiful and peaceful place full of happiness. The Firstborn (Elves) lived there for some time, too, and they learnt many things from the Valar and they were content. Compared with Christian teaching, it is quite likely, that the first people could have been learning from angels while they lived in the Paradise.
But when they listened to Devil’s suggestion and ate the fruit from the forbidden tree, they were cast out from the Paradise and banned to return there. And it is said that at that time the Paradise was removed from the Earth and hidden from people, who cannot reach it during their life since then. Similarly, when Tolkien’s Elves started to listen to Melkor, their evil qualities started to grow. This finally resulted in murdering members of their own race, which may, by the way, remind the biblical fratricide of Abel by Cain. And although the decision to leave Valinor was originally their own will, as a punishment for this killing, they were banned from returning there.
However, Valinor was not removed from Arda immediately after this accident, like the Paradise was. It happened so only many ages later because of disobedience of the second children of Ilúvatar. The whole story is really complicated, but in short it was like this: After the greatest war with Melkor, Men were awarded for their help and bravery by a piece of land, an island named Númenor, in sight of the shores of Valinor. But they too were forbidden to enter it, same as the Elves. And long time they did not mind it, until Sauron, Melkor’s follower, came to live with them. He, in the same fashion as Melkor, told them many lies and they listened to him. They stopped believing in Eru, but instead they glorified Sauron and tried to break the ban. The Valar got angry at them for this and only afterwards removed Valinor from the earth, what caused a big flood which buried whole Númenor deep under the water. And ever since then none of Men was able to reach the holy land, because it was no longer placed in this world. Apart from the general likeness of this scene to the story of Paradise, there can also be noticed one allusion to a different event from the Bible in it. For the idea of the big flood very much resembles the story of Noah and the global flood as a punishment for all the people’s misbehaviour, when nearly the whole humankind except Noah and his family stopped believing in God’s existence and turned to evil doings. Likewise, the Númenorians, except for Elendil and his family, stopped believing in the might of Valar.
Resources:
TOLKIEN, J.R.R., The Silmarillion, 1992, London: HarperCollins, 1992. 480 pp. ISBN 978-0-261-10273-6