Helaman 12:3 "Thus we see that except the Lord doth chasten his people with many afflictions, . . . they will not remember him."
Again and again Mormon reminds us that he is drastically selecting and condensing as he constructs the Book of Mormon. We can learn much about the man by examining his choices of what to include and what to leave out.
His editing may be responsible for some of the puzzling features in the scripture, such as its emphasis on warfare (Mormon was a military man) and its omission of details about the law of Moses (he was a Christian, perhaps little interested in the ancient ways after they were fulfilled by Christ's atonement and ministry).
But the choices Mormon made are perhaps most revealing when his editing shows him to be a real human being trying to draw uplifting lessons from mean and ugly events. This is manifest in two approaches: (1) a spiritual interpretation of political events and (2) drastic simplification that highlights the distinction between the obedient and disobedient.
For an example of the first point, consider the single thing Mormon chooses to tell us out of Alma's exhortation (which probably lasted for hours) to the people of Limhi in Zarahemla after their arrival there. He features Alma's statement that they "should remember that it was the Lord" that delivered them (Mosiah 25:16). When we read the account of Limhi's escape in Mosiah 22, we see that freedom came through a cunning scheme by which the people of Limhi got the Lamanite guards drunk. Yet Mormon provides a spiritual interpretation of this escape to emphasize that, despite what may seem to be men's own cleverness, planning, and apparent luck, God is really the one making things happen. Mormon's frequent "and thus we see" comments reveal this view.
Another part of Mormon's editorial approach is simplification. The people whose history he is presenting actually existed as diverse groups: the people of Zarahemla, Nephi's own descendants, the people of Ammon, Ishmaelites, Zoramites, Zeniffites, Amulonites, and so forth. Yet Mormon boils these down to just two "sides," the Nephites and the Lamanites. Why does he simplify this way? Because otherwise we might fail to draw the lesson from his record that he considers vital. His aim is not to sketch Nephite society but to turn his readers' hearts to God. That requires selection and arrangement of facts out of the hundreds or thousands of possibilities he could have presented in his record.
Another example of this simplification for a purpose is the report in Alma 16 of the surprise Lamanite attack that destroyed Ammonihah. Mormon emphasizes the hand of God behind this political-historical event. His editorial commentary teaches us that "their great city [was destroyed], which they said God could not destroy. . . . But behold, in one day it was left desolate" (Alma 16:9-10). Actually, as Alma 23-24 makes clear, the Lamanite attack on Ammonihah was triggered by events that started years before. The great Nephite missionaries, the sons of Mosiah, converted thousands of the Lamanites (the Anti-Nephi-Lehies) to the gospel. This angered other Lamanites, and they were stirred up further by Nephite dissenters. Finally in Alma 25:1-2 we learn that those frustrated Lamanites were the ones who launched the attack that struck Ammonihah without warning. The historical events leading to the destruction of Ammonihah had been very complex.
In all these matters Mormon is not ignorant of the complexity—he knew it far better than we now can know it, for his historical resources were vastly greater than ours are. He is just taking an editor's prerogative in putting things into a perspective, choosing material with a prophetic eye to the future as well as with an editor's command of his subject matter. We would do well to recognize the subtlety with which he has produced his volume to match the announced intent on its Title Page.
Based on research by Grant Hardy, July 1990, presented at greater length in "Mormon as Editor," in John Sorenson and Melvin Thorne, eds., Rediscovering the Book of Mormon (Salt Lake City: Deseret Book and F.A.R.M.S., 1990), 15-28.