The Lord of the Bible?

[Raynor]

As pointed previously, Melkor represents the fallen angel of the Bible - the most important difference being that Melkor introduces evil before the creation is completed (as noted by Tolkien in letter #212: "in this Myth the rebellion of created free-will precedes creation of the World (Eä); and Eä has in it, subcreatively introduced, evil, rebellions, discordant elements of its own nature already when the Let it Be was spoken ").

Concerning Gandalf being Christ, Tolkien stated:

Originally Posted by Letter #181

There is no 'embodiment' of the Creator anywhere in this story or mythology. Gandalf is a 'created' person; though possibly a spirit that existed before in the physical world [...] Thus Gandalf faced and suffered death; and came back or was sent back, as he says, with enhanced power. But though one may be in this reminded of the Gospels, it is not really the same thing at all. The Incarnation of God is an infinitely greater thing than anything I would dare to write. Here I am only concerned with Death as part of the nature, physical and spiritual, of Man, and with Hope without guarantees.