EKnight, you have the same inquiry I have; and it's a good one. However, I'm inclined to believe Ray's answer that the furnace of fire--alone--is figurative, and I'll try to explain why. The furnace of fire is oviously the Lake of Fire--and we all know Ray's explanation for the Lake of Fire. For example, we know the Devil, who's thrown into the Lake of Fire (Rev. 20:10) is a literal being; but we know, from Ray's teachings, that the Lake of Fire itself isn't literal. So, the Bible combines the literal with the symbolic, even in same contexts. Here's another example of this:
Genesis 3:14: "And the LORD God said unto the serpent, Because thou hast done this, thou art cursed above all cattle, and above every beast of the field; upon thy belly shalt thou go, and dust shalt thou eat all the days of thy life:"
We know that the Garden of Eden, where this took place, is a literal place (Gen. 2:10-14). We also know Satan is a literal being. But the dust represents man (Gen. 3:19). This is a parable showing God commanding Satan to hunt mankind until the end of the world.