Exodus 7:14-16

14Then Adonai said to Moses, “Pharaoh’s heart is stubborn; he refuses to let the people go.

15Go to Pharaoh in the morning as he is coming out to the water, and stand ready to meet him by the bank of the Nile. Take the staff that was transformed into a serpent in your hand.

16You are to say to him: Adonai, God of the Hebrews, has sent me to you, saying, ‘Let My people go, so they may serve Me in the wilderness,’ and behold, you have not listened.