An abridgment taken from the Book of Ether also, which is a record of the people of Jared, who were scattered at the time the Lord confounded the language of the people, when they were building a tower to get to heaven—
Comments.
Moroni was writing the title page for his father’s book. However, he had also created an important text that Mormon had indicated that the future audience should have. Thus, Moroni notes that in addition to the Book of Mormon which abridged the plates of Nephi, there was also an abridgment taken from the book of Ether. Perhaps it is important that Moroni says that it is an abridgment taken from the book of Ether rather than an abridgment of the book of Ether. As with his father’s work, there was a purpose behind what Moroni preserved of the book of Ether, and that purpose was more focused than simply providing a copy of the text of the book of Ether.
In our current edition, this sentence is set as the beginning of the paragraph. However, the next sentence begins with “which is to show”, which declares the purpose. That purpose might have also applied to the abridgment of the book of Ether, but it reads much better as the purpose of Mormon’s book. Therefore, this sentence should probably be considered as an aside. It is inserted in the text to recognize Moroni’s contribution, but the rest is a description of the purpose of the whole of the Book of Mormon.