Exodus 8:28-29

28Pharaoh said, “1I will let you go, so that you may sacrifice to the Lord your God in the wilderness; only you shall not go very far away. 2Plead for me.” 29Then Moses said, “Behold, I am going to leave you, and I will plead with the Lord that the swarms of flies may depart from Pharaoh, from his servants, and from his people tomorrow; only do not let Pharaoh 3deal deceitfully again in not letting the people go to sacrifice to the Lord.”