Exodus 11:7-9

11:7 But against any of the Israelites not even a dog will bark against either people or animals, so that you may know that the Lord distinguishes between Egypt and Israel.’ 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.”