Chapter 4 is a stark contrast to chapter 3. Where the leaders of the church were astonished at the growing numbers, the leaders of the church mourn as they see the "many dissensions in the church." The people began to contend and there was "much bloodshed."
Twice there were a large number of dissenters who tried to persuade the Lamanites to battle the Nephites. They failed the first time, but the second time they were successful. The dissenters and the Lamanites then took possession of Zarahemla and most of the Nephite's land.
What was the cause of this terrible crisis? It was the wickedness and abominations among the people and those who "professed to belong to the church of God." Could the hypocrisy of the "church members" have been the reason for many dissensions? We may never know.
Verse 12 lists all the sins of which the Nephites were guilty. The sins range from oppressing the poor to denying the spirit of prophecy and revelation to lying to dissenting. In today's society, one can easily identify an example of each of the sins by reading the news. On a bright note, I do not believe that the majority of people commit these sins. I believe that the majority of people think these sins are repulsive.
Despite some repentance and successful battle campaign's to regain their lands, the Nephites were still in a predicament. They were outnumbered by the Lamanites and the Lamanites were no longer weak. The Lamanites were now just as powerful as the Nephites and they were more numerous. This caused great fear among the Nephites.
At this point, the Nephites began to remember. They remembered the prophecies of Alma and Mosiah. They found that they had altered the laws of Mosiah and that they were wicked. They were in a state of "unbelief and awful wickedness."
As you read this chapter, you get a sense that the future does not look too good for the Nephites. Thankfully, they had great leaders who helped them get out of the quagmire they put themselves in.