The explanation given by the Savior of the things “both great and small” covered the discussion of his coming as the Triumphant Messiah.
Reference: The theme of the last days had already been touched upon, and this would be a conclusion or reemphasis of those points. The concluding sentences combine verbal elements from KJV texts with which Joseph would have been familiar.
2 Peter 3:10
10 But the day of the Lord will come as a thief in the night; in the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up.
Isaiah 34:4
4 And all the host of heaven shall be dissolved, and the heavens shall be rolled together as a scroll: and all their host shall fall down, as the leaf falleth off from the vine, and as a falling fig from the fig tree.
It is interesting that the particular language of the scroll is inaccurately applied to this new context. Note that the Isaiah imagery has heaven being rolled as a scroll, an imagery also found in Revelation 6:14. The reference here is to the Hebrew conception of heaven as a tent over the earth keeping out the celestial waters (see also 3 Nephi 24:10; Malachi 3:10). It is easy to see how a tent might be envisioned as rolling up like a scroll. The imagery of the Old Testament is one of the division between heaven and earth being removed.
The 3 Nephi context has the rolling as a scroll applied to the earth. Unlike the KJV models where only the heavens pass away, the 3 Nephi text has both heaven and earth passing. The only reference in which this altered has place is the earth as a sheet of metal under intense heat. Under that scenario, the earth could be as a flattened piece of metal that under the conditions of heat might be rolled as a scroll. This interpretation is particularly interesting for two facts. The first is that this fits much better into the imagery of Malachi where the refiner’s fire is purifying the elements. The second is that the Book of Mormon Nephites would not have had scrolls for their records, but they did have sheets of metal. When the metaphor is shifted to this new context, the purification of the fires creates something purified out of the original, and the old earth and heavens passing away into renewal through the refiner’s fire is a more tangible metaphor in the New World context.