[See the commentary on Alma 35:13]
“And Now I Return to an Account of the Wars Between the Nephites and the Lamanites”
Brant Gardner notes that Mormon's "return" to the wars between the Lamanites and the Nephites in his record (Alma 43:3) will be an all-inclusive theme through the end of the book of Alma. While we have had various descriptions of these military conflicts before, this particular discussion of war and tactics will comprise the largest stretch of such nearly pure historical material we find in the text that Mormon has edited. It becomes a legitimate question as to why we have this much war, and why it appears at this time in Mormon's text. John W. Welch reminds us:
Actually, when we closely examine the subject, we may all wonder why there isn't more war in the Book of Mormon. For many readers, encountering so much war in so sublime and sacred a volume is something of a culture shock. But this is our problem, not the book's. On this issue, if we put aside our cultural predilections and attempt to understand the Book of Mormon as a Nephite or a Lamanite might have understood it, then these events play much different, more religious roles in the book, and they become spiritually more meaningful to us. (John W. Welch, "Why Study Warfare in the Book of Mormon?" in Warfare in the Book of Mormon, p. 20)
Still, the fact of the presence of the material on war does not explain the reason for it. It is true that we may wonder what it is doing in the text and it is to that question that we turn. R. Douglas Phillips attempted an answer to the question in this way:
Mormon was also acutely aware that the final Lamanite wars . . . in which he himself played a leading military role, were the fulfillment of the prophecies . . . and a testimony that the principle of divine [covenant] retribution was in full operation (see Helaman 13:5-11; Mormon 1:19; 2:10-15). . . . Like the Greek historian Thucydides, he was not only a general, but he was also destined to be the historian who had to account for his nation's defeat in terrible war. . . . He saw as one of the main purposes of his life the tragic task of writing the "record concerning the destruction of [his] people, the Nephites" (Mormon 6:1).
Mormon devotes most of his interest in military accounts and wars to the period 75 B.C.-A.D. 25, and in particular to the fourteen years of Lamanite wars at the time of Moroni. His account of that one period fills some seventy pages in the book of Alma.
Inevitably, Mormon should have been attracted to Moroni--the brilliant, energetic, selfless, patriotic, and God-fearing hero who had been instrumental in preserving the Nephite nation. So great was Mormon's admiration for him that he named his son after him. In Mormon's eyes, the peaceful days under Moroni were a golden age in Nephite history (see Alma 50:23). But the military exploits of Moroni seem to have interested Mormon particularly. With great care, he recounted Moroni's courage and patriotism in the desperate military and political state of affairs arising from Lamanite invasion from without and sedition from within, his efforts in mobilization and defense, his own and his lieutenants' brilliant tactics, their sharply fought battles with frightful losses, and their miraculous victories. But throughout his account, we perceive the hand of God making use of devout and just military leaders and statesmen to preserve the righteous and punish the wicked (see Alma 48:11-13, Mormon's eulogy of Moroni). (R. Douglas Philips, "Why Is So Much of the Book of Mormon Given Over to Military Accounts?' Warfare in the Book of Mormon, p. 26.)
What we must understand, then, is not why there is so much war, but why there is so much emphasis on only some of the wars, wars that fall into a particular time period four hundred years before Mormon's time. The answer to that, of course has to do with the particular years, and the particular event to which they are leading. Mormon's story is a story of the expectation of, arrival of, and aftermath of, the [covenant] mission of the Atoning Messiah. [Brant Gardner, "Book of Mormon Commentary," at [http://www.frontpage2k.nmia.com/~nahualli/LDStopics/Alma/] Alma43.htm, pp. 2-4]
Note* It is worth noting that at the conclusion of these wars, Mormon notes that "they had had wars, and bloodsheds . . . for the space of many years . . . nevertheless for the righteous' sake, yea, because of the prayers of the righteous, they were spared" (Alma 62:39-40). That is, in a covenant Lord-servant relationship, the Lord will honor the petitions of his covenant obedient servant leaders, even if all of his people are not so obedient. [Alan C. Miner, Personal Notes]