Exodus 7:4

7:4 Pharaoh will not listen to you. I will reach into Egypt and bring out my regiments, my people the Israelites, from the land of Egypt with great acts of judgment.

Exodus 7:9

7:9 “When Pharaoh says to you, ‘Do a miracle,’ and you say to Aaron, ‘Take your staff and throw it down before Pharaoh,’ it will become a snake.”