The righteous will be purified and the wicked punished. The particular people who will experience Yahweh’s judgment include representatives of false gods (sorcerers), commandment-breakers (adulterers, false-swearers), and those who behave unrighteously toward others (oppressors and the inhospitable).
This list echoes themes found in the Sermon on the Mount in identifying people who violate the law and whose interpersonal relationships require improvement. Since the Nephites would have heard Jesus give that sermon the previous day, they probably saw the correlation between the two.