Well I know that Joseph Smith didn't know that "Esias" is simply a Greek form of "Elijah" -- and therefore in Doctrine & Covenants mistakenly treats them as two different people.
“Well I know that Joseph Smith didn’t know that “Esias” is simply a Greek form of “Elijah” — and therefore in Doctrine & Covenants mistakenly treats them as two different people.”
Now that you mention it, I remember the details now. His mistake (the Mormon I mentioned) wasn’t with Esaias and Isaiah, though I can see him making the same mistake since that’s how it’s spelled in the New Testament (and Smith’s way of doing theology seemed to be rather random). It was with Elias and Elijah. If I remember correctly, his argument was that Joseph Smith was Elijah all along, who was to come before the coming of Jesus Christ. When I replied that this was fulfilled by John the Baptist. He told me that John the Baptist was Elias, a different person. What a poor fellow! But it was an argument I only ever heard once, after many many debates with LDS.