And the LORD said unto Moses, See, I have made thee a god to Pharaoh: and Aaron thy brother shall be thy prophet. I have made thee a god - At thy word every plague shall come, and at thy command each shall be removed. Thus Moses must have appeared as a god to Pharaoh.
Shall be thy prophet - Shall receive the word from thy mouth, and communicate it to the Egyptian king, Exodus 7:2.