Exodus 5:1, 3

Afterward Moses and Aaron went and said to Pharaoh, “Thus says the LORD, the God of Israel, ‘Let my people go, that they may hold a feast to me in the wilderness.’”

Then they said, “The God of the Hebrews has met with us. Please let us go a three days’ journey into the wilderness that we may sacrifice to the LORD our God, lest he fall upon us with pestilence or with the sword.”