These verses end Mormon’s original Chapter XI, which covered our current Chapters 23–27. Mormon began with the story of Alma the elder in Helam, speaks of the creation of churches, and now the conversion of Alma the younger and the sons of Mosiah. The next chapters will deal with more political issues.
Important to those issues are the sons of Mosiah, and, therefore, they are named in verse 34. They were obliquely included in the end of Alma the younger’s story of preaching, and this information is essentially repeated here. The sons of Mosiah also travel through the land of Zarahemla preaching repentance. The repetition is needed precisely because they were unnamed before. They are named now, and listed separately, because they become the focus of the next major story, told in the next chapter.