Exodus 8:23KJV

21Else, if thou wilt not let my people go, behold, I will send swarms upon thee, and upon thy servants, and upon thy people, and into thy houses: and the houses of the Egyptians shall be full of swarms , and also the ground whereon they .

22And I will sever in that day the land of Goshen, in which my people dwell, that no swarms shall be there; to the end thou mayest know that I the LORD in the midst of the earth.

23And I will put a division between my people and thy people: to morrow shall this sign be.

24And the LORD did so; and there came a grievous swarm into the house of Pharaoh, and his servants' houses, and into all the land of Egypt: the land was corrupted by reason of the swarm .

25And Pharaoh called for Moses and for Aaron, and said, Go ye, sacrifice to your God in the land.