This sentiment is so close to that given my Mosiah II in Mosiah 29 that we must consider whether the sentiment was original to Ether’s record, or influence by Moroni’s interpretation of the events. Since we know that Moroni is telling the tale rather than recounting it verbatim (and again, possibly from memory) there is ample opportunity for Moroni to massage the text into “better” parallels with the Nephite history. For an ancient historian such as Moroni, this would not be seen as misrepresenting history, but rather as truly representing the cyclical nature of history.