Exodus 5 - 6

1 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.’” 2 And Pharaoh said, “Who is the Lord, that I should obey His voice to let Israel go? I do not know the Lord, nor will I let Israel go.” 3 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.” . . .
— EXODUS 5 - 6