14 These are the heads of their fathers’ households. The sons of Reuben, Israel’s firstborn: Hanoch and Pallu, Hezron and Carmi; these are the families of Reuben. 15 The sons of Simeon: Jemuel and Jamin and Ohad and Jachin and Zohar and Shaul the son of a Canaanite woman; these are the families of Simeon. 16 These are the names of the sons of Levi according to their generations: Gershon and Kohath and Merari; and the length of Levi’s life was one hundred and thirty-seven years. 17 The sons of Gershon: Libni and Shimei, according to their families. 18 The sons of Kohath: Amram and Izhar and Hebron and Uzziel; and the length of Kohath’s life was one hundred and thirty-three years. 19 The sons of Merari: Mahli and Mushi. These are the families of the Levites according to their generations. 20 Amram married his father’s sister Jochebed, and she bore him Aaron and Moses; and the length of Amram’s life was one hundred and thirty-seven years. 21 The sons of Izhar: Korah and Nepheg and Zichri. 22 The sons of Uzziel: Mishael and Elzaphan and Sithri. 23 Aaron married Elisheba, the daughter of Amminadab, the sister of Nahshon, and she bore him Nadab and Abihu, Eleazar and Ithamar. 24 The sons of Korah: Assir and Elkanah and Abiasaph; these are the families of the Korahites. 25 Aaron’s son Eleazar married one of the daughters of Putiel, and she bore him Phinehas. These are the heads of the fathers’households of the Levites according to their families. 26 It was the same Aaron and Moses to whom the LORDsaid, “Bring out the sons of Israel from the land of Egypt according to their hosts.” 27 They were the ones who spoke to Pharaoh king of Egypt about bringing out the sons of Israel from Egypt; it was the same Moses and Aaron.
28 Now it came about on the day when the LORD spoke to Moses in the land of Egypt, 29 that the LORD spoke to Moses, saying, “I am the LORD; speak to Pharaoh king of Egypt all that I speak to you.” 30 But Moses said before the LORD, “Behold, I am unskilled in speech; how then will Pharaoh listen to me?”
Moses was concerned about his physical inabilities. God had no such concerns. When God asks us to do something, He will provide the words, the ability, and will do His work through us. All He needs is a willing vessel to use.