The children of Israel did that which was evil in the sight of Yahweh: and Yahweh delivered them into the hand of Midian seven years.
"They came in as locusts ... they and their camels were without number ... they came into the land to destroy it"  (Judges 6:5).  (See my commentary on Joel for a description of the mid-east locust plagues.) Their numbers in flight sometimes even hid the sun itself.  One thing that had greatly aided the Midian invasion was the availability of camels for transporting supplies and equipment.  "A new wave of immigration into Midian from Eastern Anatolia and Northern Syria had brought to Midian the domesticated camel, thus presenting a whole new military configuration."[3] Of course, camels are referred to in  Genesis 24:10ff, but, "This is the first reference to an organized raid in which camels were used."[4]