Exodus 8:27-32

8:27 We must go on a three-day journey into the desert and sacrifice to the Lord our God, just as he is telling us.”

8:28 Pharaoh said, “I will release you so that you may sacrifice to the Lord your God in the desert. Only you must not go very far. Do pray for me.”

8:29 Moses said, “I am going to go out from you and pray to the Lord, and the swarms of flies will go away from Pharaoh, from his servants, and from his people tomorrow. Only do not let Pharaoh deal falsely again by not releasing the people to sacrifice to the Lord.” 8:30 So Moses went out from Pharaoh and prayed to the Lord, 8:31 and the Lord did as Moses asked – he removed the swarms of flies from Pharaoh, from his servants, and from his people. Not one remained! 8:32 But Pharaoh hardened his heart this time also and did not release the people.