Mormon attributed the loss of so much of the Nephite lands to the general departure of most of the Nephites from the principles of the gospel. In their dire straits, Moronihah “did preach many things unto the people.” Helaman’s sons, Nephi and Lehi, also preach repentance. Things were bad enough that the people “did repent.” As a direct result, and immediately after saying that “they did repent,” Mormon adds that “they did begin to prosper.”
That prospering was defined as being able to regain half of their property. Mormon had mentioned that Moronihah had regained half of the lost lands in Helaman 4:10. Verses 11–13 of this chapter were Mormon’s inserted moral, and he uses repetitive resumption to bring his readers back to the timeline and the story by repeating the recapture of one-half of their property in the sixty-first year (verses 16 and 17).