Do you feel Nephi’s heart when you read these verses? Do you feel his compassion, his empathy and his grief in all the things that he sees? How do you think Nephi must have felt when he was then shown these records coming forth? He probably had many emotions—tremendous excitement, hope and joy. Perhaps, he felt relief. Nephi may have also felt a burden.
When Nephi began his record, he knew he was inspired to write for "a wise purpose," but he did not know the details. Now, in the midst of this grand vision, he learned a little more about the reasons for keeping a record of sacred things. There was so much at stake. There was a tender mercy for Nephi in this experience, for him to see what would be lost and to understand the scope of what he and his posterity must do.
In all of this, we see the love and omniscience of God. Remember that Nephi was shown this vision hundreds of years before Christ was born, before the events of the New Testament, and certainly before those plain and precious things would be lost over the centuries after Christ’s death.