Exodus 8:7-9

7But the magicians (soothsayer-priests) did the same thing with their secret arts and enchantments, and brought up [more] frogs on the land of Egypt.

8Then Pharaoh called for Moses and Aaron and said, “Plead with the Lord that He may take away the frogs from me and my people; and I will let the people go, so that they may sacrifice to the Lord.”

9And Moses said to Pharaoh, “I am entirely at your service: when shall I plead [with the Lord] for you and your servants and your people, so that the frogs may leave you and your houses and remain only in the Nile?”