Exodus 7:1-3

Then the LORD said to Moses, “Now hear this: I make you as God to Pharaoh [to declare My will and purpose to him]; and your brother Aaron shall be your prophet. You shall speak all that I command you, and your brother Aaron shall tell Pharaoh to let the children of Israel go out of his land. And I will make Pharaoh’s heart hard, and multiply My signs and My wonders (miracles) in the land of Egypt.