Exodus 8:21

The magicians tried with their enchantments to produce lice, but they couldn’t. There were lice on man, and on animal.

Then the magicians said to Pharaoh, “This is God’s finger;” but Pharaoh’s heart was hardened, and he didn’t listen to them, as the LORD had spoken.

The LORD said to Moses, “Rise up early in the morning, and stand before Pharaoh; behold, he comes out to the water; and tell him, ‘This is what the LORD says, “Let my people go, that they may serve me.

I will set apart in that day the land of Goshen, in which my people dwell, that no swarms of flies shall be there, to the end you may know that I am the LORD on the earth.

I will put a division between my people and your people. This sign shall happen by tomorrow.”’”

The LORD did so; and there came grievous swarms of flies into the house of Pharaoh, and into his servants’ houses. In all the land of Egypt the land was corrupted by reason of the swarms of flies.