Chronology: The eighty-sixth year of the reign of the judges would be approximately 10 B.C. In addition to this chronological countdown, it should be noted that this commentary is using 4-5 B.C. as the date of Jesus’s birth. (See commentary accompanying 3 Nephi 1:1 for the analysis of this date.) Thus, Jesus’s miraculous birth is only five to six years in the future, but the Nephites are not improving in their gospel observance, in contrast to the Lamanites’ faithfulness.
We must remember that not all Lamanites are righteous any more than all Nephites are wicked. However, Mormon does not differentiate between the righteous/unrighteous subgroups among each people because he is heightening the contrast between the formerly righteous Nephites (now growing in wickedness) and the formerly wicked Lamanites (now becoming even more obedient to God).