After instructing his people to follow in their current path, Benjamin reminds them to take care lest the contentions rise again. We are not told specifically what those contentions were, but since Benjamin links the contentions to the “evil spirit” we may assume that they dealt with religion (and since religion was intimately associated with rulership, they dealt also with politics).
Even though Benjamin mentions his father’s teachings about the “evil spirit,” we do not have those teachings in our current Book of Mormon. We cannot tell if Mormon included it in the lost sections of Mosiah (see chapter 2) or if he elected not to discuss it at all. While we do not have the specific teachings of Mosiah1, Benjamin obviously assumed that his people remembered them.
The phrasing suggests, not a generalized attitude of negligence or disobedience, but the actual influence of an evil being. I hypothesize that Mosiah1 found himself a faithful Nephite king in a recently pagan Zarahemla. It was a Zarahemla that had lost the Old Testament religion of its founding fathers and had probably lapsed into practices adopted freely from their Mesoamerican neighbors.
Having lost their Israelite religion, Mosiah1 may have needed to teach them the concept of the “evil spirit” as one of the elements of the Israelite religion they had lost. There is no reason to believe that this “evil spirit” equates with the personage of Satan. In fact, it would be rather anachronous were it to refer to the person we understand as the devil. (See commentary accompanying 2 Nephi 2:17.) Rather, it embodies a concept that stands in juxtaposition to God and his righteousness. In the context of Mosiah1 and Zarahemla, it is most likely that the “evil spirit” was a collective designation for any and all of the Mesoamerican deities.
Vocabulary: The term “list” should be read as “incline toward” rather than “listen.”