Afterward Moses and Aaron went to Pharaoh and said, "Thus says the Lord, the God of Israel, "Let my people go, so that they may celebrate a festival to me in the wilderness.' "
But Pharaoh said, "Who is the Lord, that I should heed him and let Israel go? I do not know the Lord, and I will not let Israel go."
Then they said, "The God of the Hebrews has revealed himself to us; let us go a three days' journey into the wilderness to sacrifice to the Lord our God, or he will fall upon us with pestilence or sword."
But the king of Egypt said to them, "Moses and Aaron, why are you taking the people away from their work? Get to your labors!"
Pharaoh continued, "Now they are more numerous than the people of the land and yet you want them to stop working!"
References for Exodus 5:5
That same day Pharaoh commanded the taskmasters of the people, as well as their supervisors,