Nephi has moved the comparison from Israel entering the promised land to the current children of Israel in Jerusalem. He had noted that the difference between preservation and destruction depended upon righteousness, and now turns to the specific unrighteousness of those in Jerusalem.
This has been a story of Moses, who came long before current Jerusalem. Therefore, Nephi begins with the children of Israel reviling against Moses, and parallels that to the children of Jerusalem reviling against Lehi. The unrighteousness of those in Jerusalem signals that they would no longer be preserved, and therefore, Nephi testifies that “they are at this day about to be destroyed.”
These unrighteous children of Jerusalem are not only like the children of Israel who reviled against Moses, but lest the brothers miss the point, Nephi speaks to them directly. He says to them: “Ye are murderers in your hearts and ye are like unto them.” The brothers’ oft-stated desire to return to Jerusalem underscores how completely they are like those in Jerusalem who sought their father’s life.