During my Bible study session we came across this, in the book of Exodus:
28 Now when the Lord spoke to Moses in Egypt, 29 he said to him, “I am the Lord. Tell Pharaoh king of Egypt everything I tell you.”
30 But Moses said to the Lord, “Since I speak with faltering lips, why would Pharaoh listen to me?”
Then the Lord said to Moses, “See, I have made you like God to Pharaoh, and your brother Aaron will be your prophet. 2 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. 3 But I will harden Pharaoh’s heart, and though I multiply my signs and wonders in Egypt, 4 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. 5 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.”
6 Moses and Aaron did just as the Lord commanded them. 7 Moses was eighty years old and Aaron eighty-three when they spoke to Pharaoh.
It never really occurred to me just how terrifying a figure Moses must have been to Pharaoh (and especially Pharaoh’s officials). Moses wasn’t actually saying these predictions (of impending plagues, and cutting deals for relief), instead he was presumably just standing there while Aaron relayed the messages.