Three days in the wilderness to sacrifice. The famous line comes first: "Let my people go, so that they may celebrate a festival to me in the wilderness" (Exodus 5:1). When Pharaoh refuses, they spell it out: a three days' journey "into the wilderness to sacrifice to the Lord our God" (Exodus 5:3). After the plague of flies they ask for the same three days (Exodus 8:27).
A study Bible, the New Oxford Annotated Bible, reads this as a request for a three-day leave, not permanent freedom. Pharaoh's answer is to stop giving out straw and keep the brick count the same (Exodus 5:7-8). The same note adds that "Let my people go" later became a refrain of the spiritual "Go Down, Moses."
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