Exodus 5:2-3
5:2 But Pharaoh said, “Who is the Lord that I should obey him by releasing Israel? I do not know the Lord, and I will not release Israel!”
5:3 And they said, “The God of the Hebrews has met with us. Let us go a three-day journey into the desert so that we may sacrifice to the Lord our God, so that he does not strike us with plague or the sword.”