Exodus 8:19; Exodus 8:22

19 Then the magicians said to Pharaoh, "This is the finger of God." But Pharaoh's heart was hardened, and he did not listen to them, as the LORD had said.

22 "But on that day I will set apart the land of Goshen, where My people are living, so that no swarms of flies will be there, in order that you may know that I, the LORD , am in the midst of the land.