Textual: The “wherefore” becomes the specific transition from the introductory material into the text Nephi is going to present. I suggest that we have from this point on a recorded oral sermon from Nephi, given on two different days. The argument for the sermon is structural, with the nature of the text being much closer to Nephi’s sermons than his most recent writing, and the structure of the break between chapters 31 and 32 requiring an explanation.
As the text of 32 flows from 31, the only reason I can suggest for the firm division (entered by Nephi) is that the sermon was broken into two pieces, and thus is presented in the two pieces here. The reason for the two pieces may follow the same reasoning as we saw in Jacob’s discourse, where there was a gathering which lasted over two days, and Jacob’s speech also covered the two day period. While it is certainly only conjecture, the split over two days has a model in Jacob, and the form of this discourse is much closer to a sermon than the Nephi’s writings elaborating Isaiah.
The specific introduction to this sermon has Nephi addressing an audience. While he has done that somewhat it the exposition on Isaiah, the specific admonition to recollection appears to fit better into an audience that would be familiar with Nephi’s speeches over time rather than as one who had read them on the plates. Additionally, Nephi uses the phrase “I have spoken unto you” which further suggests a present audience. Were he exclusively referring to a modern audience that was reading his words, he might better have noted “I have written unto you,” for he certainly understood that future generations would have his word through a written medium. The format and the specific mention of speaking to an audience sets us up to see this as an included sermon, rather than a new text written specifically for the plates.