The Midianites are named in the Book of Mormon only within Nephi’s quotation of Isaiah, where their defeat at the rock of Oreb is invoked as a comparison. Isaiah foretells that the Lord of Hosts will stir up a scourge against the Assyrian “according to the slaughter of Midian at the rock of Oreb,” and will lift up his rod over the sea “after the manner of Egypt” (2 Nephi 20:26). The Midianites’ defeat belongs to the earlier Old Testament account; here it serves as the measure for the judgment to come upon the Assyrian.
The text gives no further information about the Midianites’ civilization, culture, or dealings with other peoples. They are named once, as a point of reference within the prophecy against the Assyrian.