Exodus 11:7-9

7But 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.’

8All 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.

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