Exodus 8:25-29

25Then Pharaoh called for Moses and Aaron and said, “Go, sacrifice to your God [here] in the land [of Egypt].”

26But Moses said, “It is not right [or even possible] to do that, for we will sacrifice to the Lord our God what is repulsive and unacceptable to the Egyptians [that is, animals that the Egyptians consider sacred]. If we sacrifice what is repulsive and unacceptable to the Egyptians, will they not riot and stone us?

27We must go a three days’ journey into the wilderness and sacrifice to the Lord our God as He commands us.”

28So Pharaoh said, “I 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. Plead [with your God] for me.”

29Moses said, “I am going to leave you, and I will urgently petition (pray, entreat) the Lord that the swarms of insects may leave Pharaoh, his servants, and his people tomorrow; only do not let Pharaoh act deceitfully again by not letting the people go to sacrifice to the Lord.”