On the day when the Lord spoke to Moses in the land of Egypt, he said to him, "I am the Lord; tell Pharaoh king of Egypt all that I am speaking to you." But Moses said in the Lord's presence, "Since I am a poor speaker, why would Pharaoh listen to me?"
The Lord said to Moses, "See, I have made you like God to Pharaoh, 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 Israelites go out of his land. But I will harden Pharaoh's heart, and I will multiply my signs and wonders in the land of Egypt. When Pharaoh does not listen to you, I will lay my hand upon Egypt and bring my people the Israelites, company by company, out of the land of Egypt by great acts of judgment. The Egyptians shall know that I am the Lord, when I stretch out my hand against Egypt and bring the Israelites out from among them." Moses and Aaron did so; they did just as the Lord commanded them. Moses was eighty years old and Aaron eighty-three when they spoke to Pharaoh.