Tolkien's Christian understanding of the nature of the world was fundamental to his thinking and to his major fiction. Neither propaganda nor allegory, at its root lies the Christian model of a world loved into being by a Creator, whose creatures have the free will to turn away from the harmony of that love to seek their own will and desires, rather than seeking to give themselves in love to others. This world is one of cause and consequence, where everything matters, however seemingly insignificant: action plucks on other actions, and the end of this self-love is the reduction of freedom, the imprisonment in the self, and the inability to give or receive the love that is the only thing desired. There is common ground with other great religions here, like Islam or Hinduism; and, with them, Christianity sees the universe as a place of struggle between good and evil where individuals are crucial. And evil, though in the end it will be defeated, always has the initiative, just as in Renaissance drama the machiavel, who seems fair but is foul, always has the initial advantage over those who play by the rules.

In The Silmarillion and LR many of the strategic thematic ideas are Biblical. Melkor, renamed Morgoth by Fëanor, sets himself against the One or the Creation of the One, like Satan, once the brightest of the Angels. Melkor's corruption of the ‘third theme’ of creation, that of elves and men, mirrors Satan's of Adam and Eve; and his demand for worship, offered to him at his servant Sauron's bidding in apostate Númenor, is Satanic. The Fall is a key theme: a once-perfect world corrupted. And temptation: first Melkor, then Sauron, is the Tempter, and according to their potential, all other characters are tempted. Fëanor, most skilful of the Noldor, comes to value the works of his own hands more than the gifts that made them possible. The oath he and his sons swear provokes the Elves to crime upon crime against each other. Lust for jewels and gold draws the Dwarves in Moria to delve too deep because of their desire for mithril, and wake a Balrog out of the past (or subconscious) of the world.