Exodus 8:21-22

New International Version

²¹ If you do not let my people go, I will send swarms of flies on you and your officials, on your people and into your houses. The houses of the Egyptians will be full of flies; even the ground will be covered with them.

²² “‘But on that day I will deal differently with the land of Goshen,^(A) where my people live;^(B) no swarms of flies will be there, so that you will know^(C) that I, the Lord, am in this land.