He said to him, “I am the LORD; tell Pharaoh king of Egypt everything I say to you.”
The LORD tells Moses, "I am the LORD," and commands him to tell Pharaoh everything he says.
It restates the speaker's authority and the content of Moses' task.
14These were the heads of their fathers’ houses: 15The sons of Simeon were Jemuel, Jamin, Ohad, Jachin, Zohar, and Shaul, the son of a Canaanite woman. These were the clans of Simeon. 16These were the names of the sons of Levi according to their records: Gershon, Kohath, and Merari. Levi lived 137 years. 17The sons of Gershon were Libni and Shimei, by their clans. 18The sons of Kohath were Amram, Izhar, Hebron, and Uzziel. Kohath lived 133 years. 19The sons of Merari were Mahli and Mushi. 20And Amram married his father’s sister Jochebed, and she bore him Aaron and Moses. Amram lived 137 years. 21The sons of Izhar were Korah, Nepheg, and Zichri. 22The sons of Uzziel were Mishael, Elzaphan, and Sithri. 23And Aaron married Elisheba, the daughter of Amminadab and sister of Nahshon, and she bore him Nadab and Abihu, Eleazar and Ithamar. 24The sons of Korah were Assir, Elkanah, and Abiasaph. These were the clans of the Korahites. 25Aaron’s son Eleazar married one of the daughters of Putiel, and she bore him Phinehas. 26It was this Aaron and Moses to whom the LORD said, “Bring the Israelites out of the land of Egypt by their divisions.” 27Moses and Aaron were the ones who spoke to Pharaoh king of Egypt in order to bring the Israelites out of Egypt. 28Now on the day that the LORD spoke to Moses in Egypt, 29He said to him, “I am the LORD; tell Pharaoh king of Egypt everything I say to you.” 30But in the LORD’s presence Moses replied, “Since I am unskilled in speech, why would Pharaoh listen to me?”