Exodus 5:1, 3

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

So they said, “The God of the Hebrews has met with us. Please, let us go three days’ journey into the desert and sacrifice to the LORD our God, lest He fall upon us with pestilence or with the sword.”