21 Else, if you will not let my people go, behold, I will send swarms of flies upon you, and upon your servants, and upon your people, and into your houses: and the houses of the Egyptians shall be full of swarms of flies, and also the ground on which they are.
22 And 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 in the midst of the earth.
23 And I will put a division between my people and your people: tomorrow shall this sign be.
24 And the LORD did so; and there came a grievous swarm of flies into the house of Pharaoh, and into his servants' houses, and into all the land of Egypt: the land was corrupted by reason of the swarm of flies.
25 And Pharaoh called for Moses and for Aaron, and said, Go, sacrifice to your God in the land.
26 And Moses said, It is not proper so to do; for we shall sacrifice the abomination of the Egyptians before their eyes, and will they not stone us?
27 We will go three days' journey into the wilderness, and sacrifice to the LORD our God, as he shall command us.