The ministry of the Three Nephites was not easy. There came a time when they were persecuted, and thrust into a furnace and into a den of wild beasts. Mormon is telling of stories he knows, but these are stories that will not happen for over two hundred years. Mormon will refer to them again in 4 Nephi 1:29–33.
In spite of persecutions, they persist in their labors to bring souls to the gospel of Christ.