Aaron spoke for Moses, when he went to tell Pharaoh the King of Egypt everything God wanted Moses to say. The Lord said to Moses (Exodus 7:1 to 3), "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...".