The Midianites were Arabians dwelling principally in the desert north of the peninsula of Arabia. Their progenitor was Midian, son of Abraham and Keturah. Southward they extended along the eastern shore of the Gulf of Eyleh (Sinus AElaniticus), and northward they stretched along the eastern frontier of Palestine. The influence of the Midianites on the Israelites was clearly most evil and directly tended to lead them from the injunctions of Moses. The events at Shittim occasioned the injunction to vex Midian and smite them. After a lapse of some years the Midianites appear again as the enemies of the Israelites, oppressing them for seven years, but are finally defeated with great slaughter by Gideon. The Midianites are described as true Arabs and possessed cattle and flocks and camels as the sand of the seashore for multitude. The spoil taken in the war of both Moses and of Gideon is remarkable (Numbers 31:22; Judges 8:21, 24-26). We have here a wealthy Arab nation, living by plunder, delighting in finery and, where forays were impossible, carrying on the traffic southward into Arabia, the land of gold—if not naturally, by trade—and across to Chaldea, or into the rich plains of Egypt.
Smith's Bible Names Dictionary (1866)