Then the LORD told Moses, “Get up early in the morning and stand in Pharaoh’s way as he goes down to the river. Say to him, ‘This is what the LORD says: Let my people go, so they can worship me.
If you refuse, then I will send swarms of flies on you, your officials, your people, and all the houses. The Egyptian homes will be filled with flies, and the ground will be covered with them.
But this time I will spare the region of Goshen, where my people live. No flies will be found there. Then you will know that I am the LORD and that I am present even in the heart of your land.
I will make a clear distinction between my people and your people. This miraculous sign will happen tomorrow.’”
References for Exodus 8:23
And the LORD did just as he had said. A thick swarm of flies filled Pharaoh’s palace and the houses of his officials. The whole land of Egypt was thrown into chaos by the flies.
Pharaoh called for Moses and Aaron. “All right! Go ahead and offer sacrifices to your God,” he said. “But do it here in this land.”
But Moses replied, “That wouldn’t be right. The Egyptians detest the sacrifices that we offer to the LORD our God. Look, if we offer our sacrifices here where the Egyptians can see us, they will stone us.
We must take a three-day trip into the wilderness to offer sacrifices to the LORD our God, just as he has commanded us.”
“All right, go ahead,” Pharaoh replied. “I will let you go into the wilderness to offer sacrifices to the LORD your God. But don’t go too far away. Now hurry and pray for me.”
Moses answered, “As soon as I leave you, I will pray to the LORD, and tomorrow the swarms of flies will disappear from you and your officials and all your people. But I am warning you, Pharaoh, don’t lie to us again and refuse to let the people go to sacrifice to the LORD .”
So Moses left Pharaoh’s palace and pleaded with the LORD to remove all the flies.
And the LORD did as Moses asked and caused the swarms of flies to disappear from Pharaoh, his officials, and his people. Not a single fly remained.
But Pharaoh again became stubborn and refused to let the people go.