Exodus 6:26-30

It was this Aaron and Moses to whom the LORD said, “Bring the Israelites out of Egypt by their divisions.” They were the ones who spoke to Pharaoh king of Egypt about bringing the Israelites out of Egypt—this same Moses and Aaron. Now when the LORD spoke to Moses in Egypt, he said to him, “I am the LORD. Tell Pharaoh king of Egypt everything I tell you.” But Moses said to the LORD, “Since I speak with faltering lips, why would Pharaoh listen to me?”