Melkor; Evil by Will or Evil by Nature?

[Lord Gothmog]

Gothmog, you write that Melkor had something dark in him from the beginning. But since Tolkien was a Christian, I do not believe that I am totally wrong when I compare Melkor's fall from Eru with the fall of Lucifer, Satan, from God.

Daniel, Tolkien based his stories on far more that Christianity. He drew upon many pre-Christian myths and legends, also he went to great pains to remove all religious forms from the work. So while it will obviously reflect certain beliefs of the author, it not wise to compare such things when tolkien himself said there was no intent for such comparison.

And since God is only good, or light, as you might prefer, then so is Eru.

1. How do you know that God is only good?
2. If God is how do you know that Eru is?

That means, that Melkor did not have any dark inside him from his "birth", but that it was all his own decision to become evil.

With no dark he would have been the same as Manwe who "was free from evil and could not comprehend it". Therefore Melkor had to have the darkness first else he could not have turned to Evil.