Exodus 7:2-5

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 that I may multiply My signs and My wonders in the land of Egypt. When Pharaoh does not listen to you, then I will lay My hand on Egypt and bring out My hosts, My people the sons of Israel, from the land of Egypt by great judgments. The Egyptians shall know that I am the LORD, when I stretch out My hand on Egypt and bring out the sons of Israel from their midst.”