Exodus 11:8-10

11:8 All these your servants will come down to me and bow down to me, saying, ‘Go, you and all the people who follow you,’ and after that I will go out.” Then Moses went out from Pharaoh in great anger.

11:9 The Lord said to Moses, “Pharaoh will not listen to you, so that my wonders may be multiplied in the land of Egypt.”

11:10 So Moses and Aaron did all these wonders before Pharaoh, but the Lord hardened Pharaoh’s heart, and he did not release the Israelites from his land.