Redaction: Verses 21–24 are Mormon’s sermon. These verses not only introduce the coming text but also explain why Mormon thinks this story is important. To properly understand Mormon’s point, we must realize that “nevertheless” (v. 22) is a contrast to “multiply and prosper exceedingly” (v. 21). Mormon has described a righteous people, doing righteous things and prospering as a result. Yet Mormon emphasizes that previous prosperity and righteousness are no protection from chastening and a trial of our faith.
His ultimate message is not that fortune can be quickly reversed but that Yahweh will deliver. While even the righteous suffer tribulations, they will eventually be justified and delivered because of their righteousness.
This introductory part of Alma’s story gives us some insight into Mormon’s editorial mind. Why does he choose to focus on certain stories but omit other information, particularly information historians might be interested in? Mormon’s purpose is a didactic one. He is not writing history but citing history to demonstrate the interaction between people and the Lord. We are not to learn a few historical facts, but transcendent eternal principles.
Like many in the ancient world, Mormon sees the key to the future in history’s moral lessons, because Yahweh is the same being who has ruled throughout history.