Culture: These two peoples could learn about each other’s genealogy so quickly because kinship was the chief identifier for individuals. Sorenson discusses the principle of kin interactions for a later Book of Mormon event:
When Alma had approached him, Amulek identified himself as a “Nephite” (Alma 8:20). “I am Amulek… a descendant of Nephi,” Alma 10:2–3 reports him saying. Mosiah 17:2 gives Alma’s descent in identical language. We understand, then, that the two were establishing that they belonged to the same lineage. A Mayan practice at the time of the Spanish conquest shows the same principle governing how to get along in strange territory: “When anyone finds himself in a strange region and in need, he has recourse to those of his name [kin group]; and if there are any, they receive him and treat him with all kindness.”
Understandably, therefore, one of the acts in dealing with the newcomers emerging from the wilderness would be to examine genealogies to ascertain possible kinship obligations. What they found was a supremely important kinship—one which placed the origins of both groups in Jerusalem, which by now must have nearly become the stuff of legend.
Having thus established an important bond linking them both to a common sacred origin, the Zarahemlaites welcomed their new kin appropriately: with rejoicing.