As recorded in Exodus 6, God reassured Moses after his initial failed attempt to secure the Israelites' release from Pharaoh. God reminded Moses that He had appeared to Abraham, Isaac, and Jacob as God Almighty, though His name "the LORD" (Yahweh or JEHOVAH) had not been fully revealed to them. God affirmed that He had established a covenant with the patriarchs to give them the land of Canaan and that He had heard the groaning of the Israelites under Egyptian bondage and remembered that covenant.
God then gave Moses a series of promises to deliver to the Israelites: He would bring them out from under the burdens of Egypt, free them from slavery, redeem them with an outstretched arm and great acts of judgment, take them as His own people, and be their God. He promised to bring them into the land He had sworn to give to Abraham, Isaac, and Jacob. Moses relayed these words to the Israelites, but they didn't listen to him because of their broken spirit and cruel bondage.
God then instructed Moses to go again to Pharaoh and demand that he let the Israelites go. Moses resisted, asking how Pharaoh could possibly listen to him when even the Israelites hadn't.
Exodus 6 then pauses to provide a genealogical record of the Israelite tribes, beginning with Reuben and Simeon and then focusing in detail on the tribe of Levi. The Levite lineage was traced down through several generations. This genealogy culminated in the introduction of Aaron and Moses as the sons of Amram and Jochebed, descendants of Levi. Aaron's own line was also recorded, noting his marriage and the birth of his sons and grandson.
Exodus 6 concludes by returning to the events of the time, reaffirming that it was this same Moses and Aaron whom God commanded to bring the Israelites out of Egypt. God again directed Moses to speak to Pharaoh, and Moses again expressed his doubt, saying he was of "uncircumcised lips" — meaning he felt himself to be slow of speech or stammering. So, Moses figured, Pharaoh would never listen to him.
