Exodus 7:1-7
7:1 So the Lord said to Moses, “See, I have made you like God to Pharaoh, and your brother Aaron will be your prophet.
7:2 You are to speak everything I command you, and your brother Aaron is to tell Pharaoh that he must release the Israelites from his land.
7:3 But I will harden Pharaoh’s heart, and although I will multiply my signs and my wonders in the land of Egypt,
7:4 Pharaoh will not listen to you. I will reach into Egypt and bring out my regiments, my people the Israelites, from the land of Egypt with great acts of judgment.
7:5 Then the Egyptians will know that I am the Lord, when I extend my hand over Egypt and bring the Israelites out from among them.
7:6 And Moses and Aaron did so; they did just as the Lord commanded them.
7:7 Now Moses was eighty years old and Aaron was eighty-three years old when they spoke to Pharaoh.