Exodus 8:16-19

16And Jehovah said to Moses, Say unto Aaron, Stretch out thy staff, and smite the dust of the earth, and it shall become gnats throughout the land of Egypt.

17And they did so; and Aaron stretched out his hand with his staff, and smote the dust of the earth, and there arose gnats on man and on beast: all the dust of the land became gnats throughout the land of Egypt.

18And the scribes did so with their sorceries, to bring forth gnats; but they could not. And the gnats were on man and on beast.

19Then the scribes said to Pharaoh, This is the finger of 1God! But Pharaoh's heart was stubborn, and he hearkened not to them, as Jehovah had said.