Exodus 8:27

²⁵  And Pharaoh called for Moses and for Aaron, and said, Go ye, sacrifice to your God in the land.

²⁶  And Moses said, It is not meet so to do; for we shall sacrifice the abomination of the Egyptians to the LORD our God: lo, shall we sacrifice the abomination of the Egyptians before their eyes, and will they not stone us?

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

²⁸  And Pharaoh said, I will let you go, that ye may sacrifice to the LORD your God in the wilderness; only ye shall not go very far away: entreat for me.

²⁹  And Moses said, Behold, I go out from thee, and I will entreat the LORD that the swarms of flies may depart from Pharaoh, from his servants, and from his people, to morrow: but let not Pharaoh deal deceitfully any more in not letting the people go to sacrifice to the LORD.