These two verses form the conclusion to this major event. In these verses the process that began with destruction ends in healing. The three days are here to balance with the three hours. Once again, the events that were described really did have different durations, with one measurable in hours, and the second in days. It is the presence of the same number, three, that suggests that this is a constructed time that intends to make these things parallel. In this case, there the reference is to the three days ending. This is a terminating statement.
The morning suggests that light returns. Whether or not it was related to the normal timing of sunrise is irrelevant to the author. After the symbolic three days, a new day dawns. The dissipation of the darkness is the signal that the destructions are over. Therefore there is a catalogue of the “healing” of the earth: “the earth did cease to tremble, and the rocks did cease to rend, and the dreadful groanings did cease, and all the tumultuous noises did pass away, and the earth did cleave together again, that it stood.”
The earth began to heal and cease its noise. The people began to heal, and also did cease their noise. The lamentations began to be calmed, and the grief for the dead changes to thankfulness of the living. This transformation is centered on the Messiah who spoke to them.
Textual: This ends a unit in Nephi’s text. We know that this is the end because the structure tells us that this is a conclusion to the text. We also understand both from the description of events and the way the text was constructed that Nephi crafted this description rather than simply reporting what he witnessed. The information has been presented in such a way to let us know that the event was more important that just the events that were witnessed.