In 2 Nephi 33:2 Nephi said: “there are many that harden their hearts against the Holy Spirit, that it hath no place in them.” That is the people that Jacob, as a priest, has inherited. Nephi saw it happening, and Jacob either assigns it to the reign of the second king or suggests that it has intensified. What we see at the end of verse 15 and in verse 16 is the twin evils of “many wives and concubines,” and beginning “to search much gold and silver, and began to be lifted up somewhat in pride. These are the themes of the discourse Jacob will include, beginning in the next chapter.
Both Jacob and his brother, Joseph, were consecrated priests and teachers. These titles should be seen as functions, not priesthood designations as we might see them in the modern church. It is within his responsibility as a priest and a teacher that Jacob gave a sermon to the people concerting those two troublesome developments in Nephite society.