Of course, it is not only the daughters of Ishmael who murmur. Laman, Lemuel and Ishmael’s sons are worse than the daughters. They not only mourn and murmur, they turn to planning murder.
Nephi has raised himself to Lehi’s level in the family. Both of them are responsible, and therefore, as Laman, Lemuel, and the sons of Ishmael plot murder, it is against both Lehi and Nephi. Nephi makes sure that his readers understand that the murderous men undertake their plans because they are seeing how Nephi is becoming the ruler and teacher over them. This is, of course, the point of the stories that Nephi is selecting to tell.
Nephi does not say how the word of the Lord was with them. Laman and Lemuel had already been chastised by an angel, and this might have been the audible voice of the Lord. It is also possible that the word of God came through Lehi (or perhaps Nephi, though that might have made the situation worse). However it came, it was sufficiently recognized that they turned away their anger and things returned to a more appropriate relationship in the family.
Although our Chapter 16 ends here, Nephi’s original chapter did not. The next verse followed directly, without a chapter break.