1 Nephi 8
And it came to pass that I beheld others pressing forward; and they came forth, and caught hold of the end of the rod of iron; and they did press forward through the mist of darkness, clinging to the rod of iron, even until they did come forth and partake of the fruit of the tree. And after that they had partaken of the fruit of the tree, they did cast their eyes about as if they were ashamed.
Here’s a thing about English-professor types: we look for symbols–and we are especially fond of symbols that go back to the Bible. It’s embedded in our DNA. When Tom Joad in The Grapes of Wrath kills an overseer and flees into the wilderness, we assume that he is destined to lead his people to the Promised Land—because that’s what Moses did. When a character gets swallowed by a whale (I’m looking at YOU, Pinocchio), we assume that he is going to turn his life around like Jonah did. It’s just how things always seem to work out.
The professorspeak word for this kind of symbolism is “typology” A “type” is a story or other little snippet of narrative–that connects to an “antitype” in a subsequent narrative. Jonah’s three days in the belly of a whale, for example, is a “type” that gestures to Christ’s three days in the tomb, which is the “antitype.” Typology is one of the primary ways that the New Testament connects itself to the Old Testament. Nearly every major character or event in the Old Testament can be read—and, for centuries has been read—as a type of Christ. 
Like the New Testament, the Book of Mormon connects itself to the Old Testament through typology. Nephi, the younger son who is favored by his father to the anger of his older brothers, is an antitype of the Joseph story in Genesis. The people of Lehi are saved from captivity by a prophet who leads them through the wilderness and to a Promised Land—an undeniable antitype of the Exodus narrative. Typology is as important to the opening chapters of the Book of Mormon as it is to the early chapters of the Book of Matthew—and that is saying a lot.
And then there is Lehi’s vision of the tree of life, which takes up about half of of the second chapter of the 1830 edition of the Book of Mormon (Chapter 8 in modern editions). The narrative arc of this vision—the act of eating a piece of fruit and being ashamed—is one of those stories that invariably focus our attention back to a type: the story of Adam and Eve in the Book of Genesis. But there is a difference here–and it is one with profound implications for the way that we read the entire Book of Mormon: in Lehi’s vision, eating the fruit is the right thing to do.
Let’s look at a little snippet from each of the stories stripped down to its basic narrative elements:
I know that this leaves a lot of stuff out, but work with me here. The story in Genesis says that eating a particular fruit is bad, that people should be ashamed for doing so, and that fruit-eating brought a curse upon humankind. The story in the Book of Mormon says that eating a particular fruit is good, that those who try to make us feel ashamed of the fruit are not agents of God, and that the sense of shame, not the fruit itself, is the bad thing.
If we read this as a partial correction of the Eden story, it has profound theological implications for nearly two thousand years of Judeo-Christian thought. It suggests that maybe Adam and Eve were not wrong in eating the fruit—that they did something good and necessary, and that the resulting fall was necessary to bring about the existence of humanity.
The rest of the Book of Mormon leaves no doubt that this is exactly what Lehi’s dream means. Later sermons will flesh out the idea that “Adam fell that men might be” (2 Ne 2:25). This goes well beyond the traditional Christian notion of the “Fortunate Fall”—which means that God’s goodness and power are so great that He can make even the catastrophe of the Fall work out to our benefit. The Book of Mormon suggests that the Fall of Adam was an unproblematically good and necessary thing—and that Adam would have sinned more by NOT eating the fruit than he did by eating it.
Using the connective logic of typology, Lehi’s vision it asks us to reconsider what we know about the Garden of Eden–and to wonder whether Adam and Eve might have been the heroes, not the villains or even the victims, of their story. Few Latter-day Saints realize the extent to which this would have been a thrilling, transgressive, and radically innovative way to read the Eden type in 1830. In many circles, it remains so today.
 In another life, I wrote a book about biblical typology and literature in the 17th century. It’s pretty dull and has nothing to do with the Book of Mormon, so I don’t recommend that anybody read it. But the remarkable Joseph Spencer has written a book about typology in the Book of Mormon that you should probably drop everything and read right now.