The curse of Morgoth in CoH.

[littlemanpoet]

Allow me to quote myself, since I have offered the only reasonable answer to your debate, which would have been unnecessary had you paid attention.

Originally Posted by littlemanpoet

Tom Shippey, in "Author of the Century", pointed out that Tolkien was very careful to keep evil in Middle Earth in a balance of seeming opposites. The two poles are called "Manichaean" and "Boethian". In Manichaeen, evil is considered equal to good, whereas in Boethian, Good is considered to be the ALL, and evil is merely its negative. I think Shippey was right that Tolkien was careful to keep these two poles in balance.

So to say that Melkor was evil itself, would be too Manichaean. To say that evil originated with Eru would be taking the Boethian argument too far. Both points of view are going to be able to find material in Tolkien to support your view because he put both in there. He kept them in balance. We would do well to do the same in our understanding of his works.