Exodus 8:28-29

28“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.”

29Moses 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.”