Exodus 7:1-7 NIV
Then the LORD said to Moses, “See, I have made you like God to Pharaoh, and your brother Aaron will be your prophet. You are to say everything I command you, and your brother Aaron is to tell Pharaoh to let the Israelites go out of his country. But I will harden Pharaoh’s heart, and though I multiply my signs and wonders in Egypt, he will not listen to you. Then I will lay my hand on Egypt and with mighty acts of judgment I will bring out my divisions, my people the Israelites. And the Egyptians will know that I am the LORD when I stretch out my hand against Egypt and bring the Israelites out of it.” Moses and Aaron did just as the LORD commanded them. Moses was eighty years old and Aaron eighty-three when they spoke to Pharaoh.