Jamieson, Fausset and Brown on Judges 6:33

Jud 6:33-39. The Signs.

33. all the Midianites ... pitched in Jezreel--The confederated troops of Midian, Amalek, and their neighbors, crossing the Jordan to make a fresh inroad on Canaan, encamped in the plains of Esdraelon (anciently Jezreel). The southern part of the Ghor lies in a very low level, so that there is a steep and difficult descent into Canaan by the southern wadies. Keeping this in view, we see the reason why the Midianite army, from the east of Jordan, entered Canaan by the northern wadies of the Ghor, opposite Jezreel.