Exodus 7:2-5

2You are to speak all that I command you and Aaron your brother is to speak to Pharaoh, so that he will let Bnei-Yisrael go out of his land.

3Yet I will harden Pharaoh’s heart, and multiply My signs and wonders in the land of Egypt.

4But Pharaoh will not listen to you, so I will lay My hand upon Egypt, and bring forth My armies, My people Bnei-Yisrael, out of the land of Egypt by great judgments.

5The Egyptians will know that I am Adonai, when I stretch out My hand against Egypt, and bring out Bnei-Yisrael from among them.”