Exodus 8:16-19

16Then the LORD said to Moses, “Tell Aaron, ‘Stretch out your staff and strike the dust of the earth, that it may turn into swarms of gnats throughout the land of Egypt.’”

17This they did, and when Aaron stretched out his hand with his staff and struck the dust of the earth, gnats came upon man and beast. All the dust of the earth turned into gnats throughout the land of Egypt.

18The magicians tried to produce gnats using their magic arts, but they could not. And the gnats remained on man and beast.

19“This is the finger of God,” the magicians said to Pharaoh. But Pharaoh’s heart was hardened,1 and he would not listen to them, just as the LORD had said.