Jacob allows most of the allegory to stand without any explanation. The clear references to the Nephites and the Lamanites are not pointed out. They must have been obvious, or perhaps had been taught in previous sermons. At this time, Jacob focuses on the very end of the allegory, the last days. He first testifies that the allegory is a prophecy, and that it is true.
The second time that the Lord will attempt to recover his people is during the ending of the purpose of the world. That event is so far in the Nephite future that the events are collapsed in time so that the gathering appears to be immediately prior to the pruning and when the earth would burn as fire. This directly references Jacob 5:77, which is the last verse before the end of that chapter, and the last thing Jacob would have quoted in the sermon.
However, Jacob also declares that those who are the servants to assist in the vineyard are blessed. Again, this refers to the ending of the allegory, Jacob 5:75.
Of all of the elements discussed in the allegory, Jacob’s message focuses on the final gathering and the destruction of the wicked. That appears to be the essential message for his current audience. In the previously recorded sermon, he chastised the people for beginning to stray from the gospel. In this sermon, it appears that he returns to the same theme, but without specifics. The message is still that the Nephites are beginning to follow paths that would lead to their destruction.