It is interesting that when these rebels saw how determined Moroni was to stamp out this rebellion their hearts melted within them and it says only a few continued to refuse to ratify the covenant of freedom. But to Moroni treason is treason. Here were Nephites who were willing to kill Nephite men, women, and children to gain power and support for Amalickiah. Even when given an opportunity to save their lives by taking the covenant of peace they refused. So true to his word, Moroni had them executed.
And now two things happened to achieve a new period of peace and prosperity among the people. Moroni established political stability while Helaman and his brethren struggled to establish spiritual stability.