Exodus 7:1-3

Then the Lord said to Moses, “See, I have made you as God to Pharaoh, and your brother Aaron shall be your prophet.

As for you, you shall speak all that I command you, and your brother Aaron shall speak to Pharaoh that he let the sons of Israel go out of his land.

But I will harden Pharaoh’s heart, so that I may multiply My signs and My wonders in the land of Egypt.