Exodus 8:8, 28

Then Pharaoh called for Moses and Aaron, and said, Intreat the LORD, that he may take away the frogs from me, and from my people; and I will let the people go, that they may do sacrifice unto the LORD.

And Pharaoh said, I will let you go, that ye may sacrifice to the LORD your God in the wilderness; only ye shall not go very far away: intreat for me.