Social: Jacob specifically notes that this speech is given "before your wives and children." He will be speaking mostly to the men, but the discourse is given to a mixed group. We may therefore suppose that the New World implementation of the temple concept allows both men and women into the temple precinct. The Temple in Jerusalem at the time of Christ would have had gender divisions in the various courts, but Jerusalem was a much more populous city at that time as well as when the Lehites left. In the smaller village setting, it is more logical to have a single gathering place.
In verse 8 Jacob notes that they have come to the temple "to hear the pleasing word of God." Jacob tells us more about Nephite practice here. The sermon Jacob is giving may be unusual in topic, but it is not in and of itself unusual. A sermon by the religious leader by the temple would not have been unusual. The people have an expectation of what they will hear, and that expectation must have been created by previous example. Therefore they arrive at a typical location to hear a sermon, and will suppose it to be a typical sermon. Such sermons may have been quite regular, such as every Sabbath, or they may have been periodic, occurring on special occasions.
We may also ask how people would have known to come to the sermon. It is easy enough to suppose that within the village proper oral announcement would have been sufficient. However, if this is a sermon to be given to all of the Nephites, then it should also include those who are in the fields. It would be a more difficult task to inform those more distant members of the village (who would have made up an important part of the community at this point in its development) of a special event. The most likely scenario is that this sermon is part of a predictable occasion, either a Sabbath sermon, or perhaps a sermon attached to a festival.
So far in the Book of Mormon we have relatively little information about formal sermon occasions. We have Jacob's sermon given at Nephi's behest (recorded in 2 Nephi 6-10) which itself notes that it was given over two days. I have speculated that the division between 2 Nephi 31 and 32 may also represent two parts of a sermon given on different days. The very fact of a population gathered to the village center on two consecutive days suggests a festival, and indeed Jacob's sermon was analyzed as a festival sermon by John S. Thompson (Thompson, John S. "Isaiah 50-51, the Israelite Autumn Festivals, and the Covenant Speech of Jacob in 2 Nephi 6-10." In: Isaiah in the Book of Mormon. FARMS 1981, pp. 123-150).
We have determined that Jacob may have been in charge of writing on the small plates for over thirty years, and yet he selects only this one sermon as worthy of recording on the small plates. It would appear that it is most likely that formal sermons were reserved for festival occasions when the population could be gathered, and that Sabbath services were symbolically performed in the temple and in individual homes without a congregational setting that would lend itself to a sermon. The process of selecting a sermon would then not be quite as difficult, because there would be fewer to select from. Nevertheless, we have also noted that there is an expectation of periodicity in the sermon giving. Therefore we must understand that we do not have every sermon given in the public festival setting. What criteria have Nephi and Jacob used in selecting the sermons to record?
It may be suggested that the recorded sermons are seminal discourses, those that have a purpose above and beyond the didactic and social functions of a public sermon. In the case of Jacob's sermon that Nephi records, while the doctrines are important for the modern reader, it appears that thematically the impact of the sermon was on a community struggling with meshing different ethnic groups (hence the emphasis on the salvation by the gentiles, a descriptive title that would fit the "others" that had joined with the Nephites). In Nephi's sermon, the seminal feature was the introduction of the baptismal covenant to a people who had not received that covenant in that way. In the current sermon, it is the departure from the "pleasing word of God" that they had been hearing.
We may also presume that in the course of developing a society, most of the sermons would have been supportive of the group and fostering group cohesion. This sermon is very different in that it particularly addresses divisions in the group, and condemns them. Thus while supporting the group in its entirety, it is doing so by attacking those who have become among the most powerful in the group - the wealthy men. This is a dangerous tactic in a small social setting, and it would be this bold move so contrary to previous sermons, but demanded by the Lord, that warranted the inclusion on the small plates.