Exodus 8:25

23I will put a division between my people and your people. This sign shall happen by tomorrow.”’”

24The LORD did so; and there came grievous swarms of flies into the house of Pharaoh, and into his servants’ houses. In all the land of Egypt the land was corrupted by reason of the swarms of flies.

25Pharaoh called for Moses and for Aaron, and said, “Go, sacrifice to your God in the land!”

26Moses said, “It isn’t appropriate to do so; for we shall sacrifice the abomination of the Egyptians to the LORD our God. Behold, if we sacrifice the abomination of the Egyptians before their eyes, won’t they stone us?

27We will go three days’ journey into the wilderness, and sacrifice to the LORD our God, as he shall command us.”