As already mentioned, Mosiah appears to prepare for political upheaval, even war, among his people, and transfers into Alma1’s care the records and the interpreters—but not the Liahona or the sword of Laban. Apparently these items were associated with the political, rather than the religious, rule.
The separation of the religious leader from the political leader is mirrored in the separation of sacred artifacts. The Liahona and sword of Laban remain with the political side and the sacred records move to a different lineage as their caretakers. These records will move in and out of the political transmission lines from this point until Mormon himself.
Text: In the 1830 edition the chapter ends with our verse 19. This verse is the beginning of a new chapter, and a new idea for Mormon the editor.