Mormon is hardly detached from what he is writing. He has a purpose in mind, and while he most often allows the stories to teach their own lessons, there are times when he inserts his own moral of the story. That is what is happening in these verses. Mormon has departed from telling the story to commenting on the lessons to be learned from the story. Even though he has told his readers little of Helaman the Chief Judge, he has indicated that Helaman kept the commandments. Mormon further noted that under Helaman’s rule, the people also kept the commandments. That obedience invoked the covenant, and they prospered. Mormon elaborates on the blessings that God may shower upon his faithful people.
It is also important to note that Mormon’s text often shows Lamanites becoming Nephites, Nephites who are often more faithful than those who were born Nephites. Here, Mormon declares that the reason for this is that “the Lord is merciful unto all who will, in the sincerity of their hearts, call upon his holy name.”
One’s ethnicity does not matter. One’s politics do not matter. One’s previous deviation from the commandments does not matter. What matters is that “whosoever will, may lay hold upon the word of God.” All may “land their souls … at the right hand of God in the kingdom of heaven.”