Sociological: This is an incredibly final statement. This is an absolute farewell, most appropriate to a dying man - yet Jacob clearly lives for years after this discourse, as will be apparent in the next chapter. Why the finality of this statement?
Sperry suggests: "It is very probable that Jacob meant to end his book at this point; the quotation seems to imply that fact. However, later events caused him to add the historical matter now found in the last chapter of his record." (Sperry, Sidney B. Book of Mormon Compendium. Bookcraft, 1968, p. 266).
The problem with this analysis is that it recognizes the finality of the statement, but misses the intended audience. Jacob is speaking to a present audience when he delivers that statement, unlike his actual final statement at the end of chapter 7:
" Jacob 7:27 And I, Jacob, saw that I must soon go down to my grave; wherefore, I said unto my son Enos: Take these plates. And I told him the things which my brother Nephi had commanded me, and he promised obedience unto the commands. And I make an end of my writing upon these plates, which writing has been small; and to the reader I bid farewell, hoping that many of my brethren may read my words. Brethren, adieu."
In his actual final statement there is no question but that Jacob is speaking to the readers of his text. In the present case, however, this is the final statement of a recorded sermon. It is that present context that makes the statement most fascinating, and suggests a rather different explanation.
This is complete speculation built on a very few fragments of evidence, but I suggest that we have in this discourse the final discourse of Jacob as a head priest. What is final is not his life, but his position, and the termination of his functioning in that position is the reason for the finality of the benediction. His farewell is a formal one, which places his position as a mouthpiece for God against their actions, and declares that the ultimate judgement between them (the congregation he is exhorting and himself) will be at the bar of God.
What evidence may be presented for this hypothesis? The first is the discussed marginalization of Jacob. He has little power, and exerts none but the power of personal testimony in this discourse. Secondly, there is very clearly a cultural shift occurring in the population, evidenced by the social divisions occasioned by the practice of multiple wives (and probably wife-exchange, as noted earlier). This influx of ideas from outside influences has been sufficiently powerful that not only have many followed in these foreign cultural practices, but those who have done so are the wealthy who apparently are gaining greater say in the governance of the community.
The gulf between the practices of the community and the exhortations of Jacob as chief high priest would have been tremendous, and certainly Jacob intended to make them as obvious and painful as possible. Since the evidence of this sermon suggests that there was little or no repentance after his first sermon, we would have the situation of a prophet verbally attacking the character of the leaders of the community. That is a situation that such leaders would not long endure, and since they have not conformed themselves to Jacob's requests for repentance, the next logical step would be for the removal of Jacob from an official position.
This suggested removal of Jacob from a position in the official religious structure explains some interesting subtleties in the story of Jacob and Sherem in the next chapter.