One wonders if there isn’t some mistake in this passage. The expression “the more wicked part of them”, referring it would seem to the Gaddianton robbers, doesn’t make much sense. A more reasonable interpretation is that the Lamanites hunted down these robbers, killing the more wicked part of them but preaching to the less wicked part, thus eliminating them. Earlier in my work on the text, I proposed that Mormon himself accidentally wrote “the more wicked part of them” instead of the intended “the less wicked part of them”. Perhaps he conflated the two ideas of “preaching to the less wicked” and “killing the more wicked”, ending up with “preaching to the more wicked”. For this proposed emendation, see page 65 of Uncovering the Original Text of the Book of Mormon: History and Findings of the Critical Text Project, edited by Gerald Bradford and Alison Coutts (Provo, Utah: FARMS, 2002). Another possibility is that “the more wicked part of them” was introduced here into verse 37 because of its correct occurrence in the following verse:
Also note that such an error in verse 37 (of more for an original less) could have entered the text as Joseph Smith dictated this passage or when Oliver Cowdery copied it from 𝓞 into 𝓟.
But there is a much better and obviously correct solution to the difficult reading here in verse 37, one proposed by Paul and Rachel Jenkins (personal communication, 18 November 2005)— namely, there is no need to make any change here, just a recognition that the pronoun them in “the more wicked part of them” in Helaman 6:37 does not refer to the Gaddianton robbers but to the Lamanites. This interpretation is supported by the explanation earlier in this chapter:
Thus in verse 37, by converting the more wicked Lamanites and by hunting down the Gaddianton robbers, the Lamanites totally eliminated the Gaddianton robbers and their influence from among their own people. In fact, the same kind of interpretation applies to the them in the phrase “the more wicked part of them” in verse 38: “the Nephites did build them up and support them beginning at the more wicked part of them”; that is, the more wicked part of the Nephites supported the Gaddianton robbers, allowing them to thrive among the Nephites until those robbers spread throughout the Nephites. The critical text will therefore accept the earliest text in Helaman 6:37 with the understanding that the pronoun them in “the more wicked part of them” refers to the Lamanites, not to the Gaddianton robbers.
Summary: Maintain in Helaman 6:37 the original text, “the more wicked part of them”; here the text explains that the Lamanites preached unto the more wicked Lamanites, converting them, and thus undermining the support the Gaddianton robbers received among the Lamanites.