In Alma 4:3 we are informed that because of the war, "every soul had cause to mourn; and they believed that it was the judgments of God sent upon them because of their wickedness and their abominations."
Now the Nephites are supposed to be the victors here, so why is every soul mourning? And why do they believe their are being judged of God because of their wickedness and abominations? What wickedness and abominations. The answer might lie at the root of the contentions. The reader should not assume that every person who had sympathies for the Amlicites had joined them. There were probably a number of those in the land of Zarahemla who had a desire for many of the things espoused by the Amlicites. This is most likely the nature of their abomination and wickedness. But if "every soul had cause to mourn, what about the righteous Nephites? What was their sin? The answer is noted by Mormon in what they did (implying what they had not done). Mormon writes that the people "awakened to a remembrance of their [covenant] duty" and that "they began to establish the church more fully." How do you "establish" a church more fully? The answer, at least in part, is that every member becomes a teacher and a missionary. In other words, part of the covenant responsibility of the Nephites was to take that gospel to those who did not understand it well or did not even share in it. To "establish a church more fully" implies that the Nephites finally awakened to their covenant responsibility to share it. This not only involved strengthening those within the church, but teaching those without, thus overcoming the precise ideas espoused by the Amlicites which caused the contention in the first place. In other words, the righteous Nephites repented by sharing the gospel and the unrighteous Zarahemlaites repented by accepting the gospel. [Alan C. Miner, Personal Notes] [See the commentary explaining "establish the church more fully"--Alma 6:4]