If chapter five ends with worry about God's actions on behalf of Israel (seems worse now that God is involved!), chapter six begins with a promise that all will be well. In 3:19 The Lord tells Moses that He knows Pharaoh will not allow the people to go with out a chazak yad (strong hand), here that expression is repeated twice; however the ambiguity of Hebrew means that the Pharaoh may drive Israel out with a strong hand (meaning he can't get them out fast enough) or that a strong hand (God's or Moses') will force him to release the people. (this type of verbal ambiguity is a common feature of the Hebrew text)
Verse 2 seems to introduce a different version of the story, including a claim that contradicts Genesis. (Scholars theorize that this is part of the Priestly account.) The Lord confronts Moses and tells him His Name. One reason scholars see another hand at work is found in v3 where He
says, "I was not known to them by my name YHWH. Friedman points out that
Genesis 13:4 ("There Abraham called out the name YHWH), 15:2 (Abraham
said, "My Lord YHWH..."), Gen 22:14&16, Isaac in Gen 26:2 and 26:25
(Isaac build an altar and called out the name YHWH) and, finally, at
Jacob's vision of the ladder Gen 28: 13 (YHWH was standing over against
him. He said, "I am YHWH, the God of Abraham and the God of Isaac) and
28:16 (Jacob said, "YHWH is in this place and I did not know it.") In
the Priestly account the name is revealed to Moses but not the
Patriarchs. From Friedman's perspective, the covenant with Noah is with elohim (GOD), with Abraham it is El Shaddai and henceforth, the covenant name is YHWH (see the next verse!).
"I am YHWH" follows a common verbal pattern found in ancient Near East documents in reference to kings and deities. (Alter) It concludes with the affirmation that Israel will know He is YHWH God when He delivers them. As in 2:24, this account connects the intervention of God to the three Patriarchs, here identifying Himself as El Shaddai (translated as "Mighty God"--it occurs six times in Genesis. Half of the 48 OT uses of the word occur in Job. It comes from the root to destroy, powerful destruction. Jeremiah has this term many times). Here God hears the cries and remembers the covenant. The second of the three declarations ("I am YHWH") follows, using four active verbs to express what His powerful presence will mean. YHWH God will "bring you out from under," "rescue" (natsal-snatch away, rescue, save), "redeem" (ga'al- next of kin who redeems a slave) and "take you" (this verb will occur in the genealogy indicating marriage). The special relationship (My people//your God) is often expressed in marital, adoptive, or parental terms.
6:9 The narrative has a different explanation of events. Moses speaks to Israel but they do not listen because they had "short spirit" and heavy labors. Undeterred, YHWH speaks to Moses and to Aaron and tells them to speak to Pharaoh. Moses response is similar to previous account, although here he says that he has "uncircumcised lips." The exact meaning is unsure and much debated--with a wide possibility of meanings. Generally, uncircumcised is an indication of outsider status (not part of Israel) and when applied to "other" body (e.g. uncircumcised heart) refers to a lack of openness and faith/faithfulness to God. It does seem to function as an expression of a "barrier" to success which explains Israel's failure to respond (and a worry Pharaoh won't either). Without direct response to Moses. YHWH then addresses both he and Aaron. God tsavah (command, used 517x in Bible) them both to Israel and Pharaoh to bring the Children of Israel out of Egypt. The entire section seems to be another version of the call narrative in Exodus 3, (identified as another source) but functions now as an intensifier.
Suddenly a genealogy appears, which begins with Reuben and Simeon (first two sons of Jacob) but focuses on Levi. The purpose is to explain the genealogy of Moses and Aaron. The wording "this is the Moses and Aaron who..." (6:26-27) makes it sound like the genealogy came from another place. The names of the parents are given (Amram marries his father's sister Jochebed) finally. The function of genealogy is to legitimize the person based on their lineage.
The chapter concludes with a reiteration of sort of the verses prior to the genealogy, with the exception of Aaron's name. The "I am YHWH" and 'uncircumcised lips' is repeated. The flow of the story continues into chapter 7.