Nephi's vision of the tree of life, among the best-known passages in the Book of Mormon, expands upon the vision received earlier by his father, Lehi.
"And it came to pass that the Spirit said unto me: Look! And I looked and beheld a tree; and it was like unto the tree which my father had seen; and the beauty thereof was far beyond, yea, exceeding of all beauty; and the whiteness thereof did exceed the whiteness of the driven snow.
"And it came to pass after I had seen the tree, I said unto the Spirit: I behold thou hast shown unto me the tree which is precious above all.
"And he said unto me: What desirest thou?
"And I said unto him: To know the interpretation thereof" (1 Nephi 11:8-11).
Because Nephi wanted to know the meaning of the tree that his father had seen and that he himself now saw, we would expect "the Spirit" to answer Nephi's question. But, instead, Nephi is first shown a young virgin and then, after an interval, sees the same virgin holding a child in her arms. And he is told that she is "the mother of the Son of God, after the manner of the flesh" (1 Nephi 11:18).
Then "the Spirit" asks Nephi the question that Nephi himself had posed only a few verses before: "Knowest thou the meaning of the tree which thy father saw?" (1 Nephi 11:21).
Strikingly, though the vision of Mary seems irrelevant to Nephi's question — for the tree is nowhere mentioned in the angelic guide's response — Nephi himself now replies that, yes, he knows the answer (1 Nephi 11:22-23).
How has Nephi come to this understanding? Clearly, the answer to his question about the meaning of the tree lies in the virgin mother with her child. It seems, in fact, that the virgin actually is the tree, in some sense. Even the language used to describe her echoes that used for the tree. Just as she was "exceedingly fair and white," "most beautiful and fair above all other virgins," so was the tree's beauty "far beyond, yea, exceeding of all beauty; and the whiteness thereof did exceed the whiteness of the driven snow." Significantly, though, only when she appeared with a baby and was identified as "the mother of the Son of God" did Nephi grasp the tree's meaning.
Why would Nephi see a connection between a tree and the virginal mother of a divine child? His vision seems to reflect a meaning of the "sacred tree" that is unique to the ancient Near East and, in Israelite history, specifically to the period before the Babylonian captivity — Nephi's era. This can only be fully appreciated when the ancient Canaanite and Israelite associations of that tree are borne in mind.
Recent scholarship, including archaeological finds, has demonstrated that the goddess Asherah, worshipped among Israel's Canaanite neighbors as the wife of the supreme god, El, was also revered by many Israelites as the consort of El(ohim) and the (in some accounts, virginal) mother of his children. She was symbolized by a tree, and, in fact, a representation of such a tree stood within the temple at Jerusalem during the time of Lehi.
Asherah's worship had become associated with fertility rites and immorality, though. Prophets had long condemned it and, by the time of Israel's return from Babylonian exile, Jewish opposition to Asherah was universal. And so Asherah was expunged from the history of Judaism. In our text of the Bible, filtered and reshaped as it appears to have been by reforming Deuteronomist priests around 600 B.C., hints of the goddess remain, but little survives to give us a detailed understanding of her character or nature. An early Hebrew like Nephi, however, would immediately have understood the representation, by a tree, of a virginal mother of a divine son.
The inclusion in 1 Nephi of an authentically pre-exilic religious symbol that could scarcely have been derived by a New York farm boy from his Bible strongly suggests that the Book of Mormon is, indeed, an ancient historical record in the Semitic tradition.
For a much more detailed examination of this topic, see Daniel C. Peterson, "Nephi and His Asherah: A Note on 1 Nephi 11:8-23," online at maxwellinstitute.byu.edu, or the shorter (and, to its author, less adequate) version of the article online at http://maxwellinstitute.byu.edu/publications/jbms/?vol=9&num=2&id=223.