19 Then the magicians said unto Pharaoh, This is the finger of God: and Pharaoh's heart was hardened, and he hearkened not unto them; as the LORD had spoken.
20 And the LORD said unto Moses, Rise up early in the morning, and stand before Pharaoh; lo, he cometh forth to the water; and say unto him, Thus saith the LORD, Let my people go, that they may serve me.
21 Else, if thou wilt not let my people go, behold, I will send swarms of flies upon thee, and upon thy servants, and upon thy people, and into thy houses: and the houses of the Egyptians shall be full of swarms of flies, and also the ground whereon they are.
22 And I will sever in that day the land of Goshen, in which my people dwell, that no swarms of flies shall be there; to the end thou mayest know that I am the LORD in the midst of the earth.
23 And I will put a division between my people and thy people: by tomorrow shall this sign be.
24 And the LORD did so; and there came grievous swarms of flies into the house of Pharaoh, and into his servants' houses: and in all the land of Egypt the land was corrupted by reason of the swarms of flies.
25 And Pharaoh called for Moses and for Aaron, and said, Go ye, sacrifice to your God in the land.