Exodus 8:7-9

7But the magicians were able to do the same thing with their magic. They, too, caused frogs to come up on the land of Egypt.

8Then Pharaoh summoned Moses and Aaron and begged, “Plead with the Lord to take the frogs away from me and my people. I will let your people go, so they can offer sacrifices to the Lord.”

9“You set the time!” Moses replied. “Tell me when you want me to pray for you, your officials, and your people. Then you and your houses will be rid of the frogs. They will remain only in the Nile River.”