Exodus 8:18-22

18When the magicians attempted to bring forth gnats by their secret arts, they could not. So there were gnats on people and on animals.

19The magicians said to Pharaoh, “It is the finger of God!” But Pharaoh’s heart remained hard, and he did not listen to them, just as the Lord had predicted.

20The Lord said to Moses, “Get up early in the morning and position yourself before Pharaoh as he goes out to the water, and tell him, ‘Thus says the Lord, “Release my people that they may serve me!

21If you do not release my people, then I am going to send swarms of flies on you and on your servants and on your people and in your houses. The houses of the Egyptians will be full of flies, and even the ground they stand on.

22But on that day I will mark off the land of Goshen, where my people are staying, so that no swarms of flies will be there, that you may know that I am the Lord in the midst of this land.