EXO 3:18

18 My people will do what you say. Then you and their leaders must go to the king of Egypt, and you must say to him, ‘Yahweh, who is God, the one we Hebrews [worship], has revealed himself to us. So now we ask you to allow us to travel for three days to [a place in] the desert, in order that there we may offer sacrifices to Yahweh, our God.’