Exodus 6:26-30

These are that Aaron and Moses, to whom Jehovah said, Bring out the children of Israel from the land of Egypt according to their hosts. These are they that spake to Pharaoh king of Egypt, to bring out the children of Israel from Egypt: these are that Moses and Aaron. And it came to pass on the day when Jehovah spake unto Moses in the land of Egypt, that Jehovah spake unto Moses, saying, I am Jehovah: speak thou unto Pharaoh king of Egypt all that I speak unto thee. And Moses said before Jehovah, Behold, I am of uncircumcised lips, and how shall Pharaoh hearken unto me?