Exodus 8:20-21 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. 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.
The fourth plague sent upon Egypt was swarms of flies. But not upon the land of Goshen, where the children of Israel lived. Only upon Egypt, it was so bad Pharaoh agreed to let them go for 3 days. But when the Lord removed the flies, Pharaoh changed his mind.
Exodus 8:20-32 records the complete account.
⇛ continue to Plague #5
⇛ return to Plagues on Egypt