19 The magicians told the king, “God has done this.”But, as the Lord had said, the king was too stubborn to listen.
20 The Lord said to Moses:Early tomorrow morning, while the king is on his way to the river, go and say to him, “The Lord commands you to let his people go, so they can worship him.
21 If you don't, he will send swarms of flies to attack you, your officials, and every citizen of your country. Houses will be full of flies, and the ground will crawl with them.
22-23 “The Lord's people in Goshen won't be bothered by flies, but your people in the rest of the country will be tormented by them. That's how you will know that the Lord is here in Egypt. This miracle will happen tomorrow.”
24 The Lord kept his promise—the palace and the homes of the royal officials swarmed with flies, and the rest of the country was infested with them as well.
25 Then the king sent for Moses and Aaron and told them, “Go and sacrifice to your God, but stay here in Egypt.”
26 “That's impossible!” Moses replied. “Any sacrifices we offer to the Lord our God would disgust the Egyptians, and they would stone us to death.