Exodus 8, 21 – 28 „Then Pharaoh summoned Moses and Aaron and said, Go sacrifice to your God within the land. 22But Moses replied, It is not right to do so, for what we sacrifice to the LORD, our God, is abhorrent to the Egyptians. If we sacrifice what is abhorrent to the Egyptians before their very eyes, will they not stone us? 23We must go a three days’ journey in the wilderness and sacrifice to the LORD, our God, as he commands us. 24Pharaoh said, I will let you go to sacrifice to the LORD, your God, in the wilderness, provided that you do not go too far away. Pray for me. 25Moses answered, As soon as I leave you I will pray to the LORD that the swarms of flies may depart tomorrow from Pharaoh, his servants, and his people. Pharaoh, however, must not act deceitfully again and refuse to let the people go to sacrifice to the LORD. 26When Moses left Pharaoh, he prayed to the LORD; 27and the LORD did as Moses had asked, removing the swarms of flies from Pharaoh, his servants, and his people. Not one remained. 28But once more Pharaoh became obstinate and would not let the people go”.