Exodus 6

Exodus 6:1 Now shalt thou see what I will do to Pharaoh: for with a strong hand shall he let them go
Mark E. Petersen
The Lord was now ready to perform miracles… to harass the Egyptians into submission. Some were defiantly duplicated by the magicians. But then the plagues came. The Nile was turned to blood. The fish died. There was an invasion of frogs. Pharaoh prayed for deliverance from them. The plague of lice followed, making Pharaoh more bitter and stubborn.
The flies and murrain were next, but although the Egyptians suffered, the Israelites in the land of Goshen were free from it all. Next came the boils, which affected even the magicians, regardless of their magic.
Hail and locusts now afflicted Egypt, but none were found in Goshen. At last the king began to relent. But it wasn't enough, so darkness came upon the land except in Goshen, where there was light. Pharaoh weakened a little more, but even yet he refused to free the slaves.
And then came the final blow—the death of the firstborn of all life in Egypt, again excepting the Israelites, who were saved by the Passover.
Not only did Pharaoh permit the Israelites to leave; he commanded them to go. The Egyptian people themselves hurried the Israelites in their departure, fearing that even they themselves would die, as had their firstborn children. (Moses: Man of Miracles [Salt Lake City: Deseret Book Co., 1977], 61-62)
Exodus 6:3 by my name JEHOVAH was I not known to them
“A modern translation of the Hebrew consonants JHWH, being the sacred name of the God of Israel. Latter-day revelation identifies Jehovah as Jesus Christ (D&C 110:3; 3 Ne. 15:5). In The Church of Jesus Christ of Latter-day Saints standard usage applies this term to Jesus Christ beginning in, but not limited to, his premortal estate, as distinct from Elohim, who is the Father. In the King James Version ( King James Version) Old Testament, Jehovah is presented as LORD in capitals and small capitals, whereas Elohim is translated God.” (Robert J. Matthews, Behold the Messiah [Salt Lake City: Bookcraft, 1994], 74)
Long before Moses, the Lord declared, “Abraham, Abraham, behold, my name is Jehovah.” (Abr. 1:16; 2:8).  Was Moses the first prophet to know the Lord by the name of Jehovah?  That can’t be right.  Joseph Smith corrects this passage to read, “I appeared unto Abraham, unto Isaac, and unto Jacob.  I am the Lord God Almighty; the Lord JEHOVAH. And was not my name known unto them?”  And what about the patriarchs, were Abraham, Isaac, and Jacob the first to know the Lord as Jehovah?  Wouldn’t other prophets have known the Lord well enough to know Him by name?
The first was “Adam, who was the son of God, with whom God, himself, conversed” (Moses 6:22).  Adam was told to teach his children of the Father, “Man of Holiness is his name, and the name of his Only Begotten is the Son of Man” (Moses 6:57).  What are the chances Adam knew the name of Jehovah?  Pretty good.  Secondly, “God revealed himself unto Seth” (Moses 6:3), then why not by name? Next, Enoch walked and talked with God (Moses 6:34), and Noah and Melchizedek held priesthood keys and knew the Lord.  Don’t forget about the brother of Jared—truly to him was something new and amazing revealed (Ether 3:15-16).
Jehovah’s name was not new to the prophets but to the scribes responsible for this belated Hebrew version of the story (i.e. Exodus).  Indeed, the name of Jehovah, written without vowels as JHVH in Hebrew appears 4 times in the Old Testament:  Ex. 6:3; Ps. 83:18; Isa. 12:2; 26:4.  The first appearance in surviving Hebrew scripture was this revelation to Moses. Traditionally, the Jews never spoke the name, holding it too sacred to be uttered by mortal lips.  Hence, “in reading, [they] never mentioned it, but substituted one of the other names of God, usually Adonai” (Bible Dictionary:  Jehovah).
Jeffrey R. Holland
Because of this reverence for titles and the meanings they conveyed, the name Jehovah, sometimes transliterated as Yahweh, was virtually unspoken among that people. This was the unutterable name of Deity, that power by which oaths were sealed, battles won, miracles witnessed. Traditionally, he was identified only through a tetragrammaton, four Hebrew letters variously represented in our alphabet as IHVH, JHVH, JHWH, YHVH, YHWH.
Since those early days of the Hebrews, others have thought the attempt to know the Lord God of Israel by naming him was both irreverent and impossible… we try to know better the great Jehovah, the Lord Jesus Christ… So, while we must be fully aware of the limitations—in our lives, in our language, in our ability to comprehend or appreciate—we still do well to praise Deity by name and in some small way come to know him better by what he says he is. Men should be aware, and beware, "how they take my name in their lips." (D&C 63:61.) (However Long and Hard the Road [Salt Lake City: Deseret Book Co., 1985], 16)
Exodus 6:7 I will take you to me for a people, and I will be to you a God
This language suggests the Israelites had fallen into some degree of apostasy.  If so, then Moses was a restorational prophet like Elias, Jesus, Joseph Smith, etc.  Certainly, the great apostasy was not the only apostasy. Elder Tad Callister wrote:
“Since God loves all his children in all ages, his gospel was introduced to the earth in the beginning of time… but eventually it was rejected… This pattern repeated itself in the days of Enoch, Noah, Abraham, and Moses (Mark 12:1-9).  Each period when the gospel was committed to the earth is called a dispensation, and each period when it was rejected and ultimately lost from the earth is called an apostasy.” (The Inevitable Apostasy, xi)
In the behavior of the Hebrews after the Exodus, we will see a people who have forgotten the Lord and his commandments.  Every commandment seems new and too difficult for them, but God is still willing to take them to be his people. 
“Throughout the rest of the Old Testament, the mercy and grace of the Lord toward his people is remembered in the miraculous events of the Exodus, when the Lord heard the cries of his covenant people in Egypt, delivered them from bondage, met them at Sinai where he established a new covenant with them, and led them into the promised land. The accompanying obligations of the Mosaic covenant were explicitly set forth in detail, both in terms of ethical behavior as well as ritual, in the Law of Moses. The Lord defined the relationship thus: ‘And I will take you to me for a people, and I will be to you a God’ (Ex. 6:7; Jer. 31:33) and explained the accompanying obligations, ‘Ye shall be holy; for I am holy’ (Lev. 11:44; 19:2; 20:26). To the Mosaic covenant were attached blessings and curses: obedience would bring prosperity and protection, whereas disobedience would bring death and destruction. The sacred history of Israel recounts centuries of Israel's struggle to understand, remember, and keep the conditions of the covenant — a struggle that most often ended in apostasy. To regulate the covenant, the Lord sent prophets to his people. Their message was always the same: repent or face the acknowledged consequences. Through the conditions of the covenant, disobedience warranted the justice of God, which meant judgment and destruction. Yet the prophets always reminded the people that ultimately, through God's mercy, restoration and rebuilding would come.” (Kent P. Jackson, ed., Studies in Scripture, Vol. 4: 1 Kings to Malachi [Salt Lake City: Deseret Book Co., 1993], 235 - 236)
Exodus 6:12 how then shall Pharaoh hear me, who am of uncircumcised lips?
When first called, Moses worried about his public speaking, “I am not eloquent…  I am slow of speech, and of a slow tongue” (Ex. 4:10).  In chapter 6, he uses a circumcision metaphor, “how then shall Pharaoh hear me, who am of uncircumcised lips?”  This is a literary anachronism.  The institutionalization of circumcision likely came well after Moses’ day.  We have already discussed how Moses forgot to circumcise his son which displeased the Lord (Ex 4:24-26).  It’s hard to believe that Moses would have used such an odd phrase as “uncircumcised lips” when the token was something he forgot.  Who gets their lips circumcised anyway?
On the other hand, circumcision was very important to the priests and scribes of later generations.  In order to understand the rest of Exodus 6, we have to imagine these later priests and scribes including in the text elements that were important to them, like circumcision and the genealogy of Aaron, from whom the priests and high priests descended.
Exodus 6:14-15 the firstborn sons of Reuben and Simeon
These verses are the beginning of a scribal insert which makes no sense chronologically or doctrinally.  We are cruising along with the story of Moses and Pharaoh, and all of the sudden we are getting a genealogy lesson on Reuben and Simeon.  The reason is because some priestly scribe is trying to establish the genealogy of Aaron through Levi.  He starts with the elder sons of Leah, Reuben and Simeon, then gets to his focus—Levi.  Fortunately, for us, he doesn’t find it necessary to go through the other 9 tribes.
Exodus 6:16-25 these are the names of the sons of Levi
Now we are getting to something important for a priest, the Levitical line of authority. 
“This section is the work of the writer whom we call P. It is much later than the other accounts of the call of Moses...
“The purpose of this jumbled section (verses 10-30) is to prepare the way for the selection of Aaron as the partner of Moses (Ex 7:1-7)... 
“…no reference is made to the family of Moses, while full information is given about the wives and children of Aaron and Eleazar.  Every royal or priestly hereditary line has to see to it that history backs up its claims to a clear pedigree...
“The genealogist is concerned to show that the priest has played an active role in the founding of the nation; his list symbolizes the legitimacy and authority of the priesthood in his own day.”
(The Interpreter’s Bible, ed. by G. A. Buttrick et al [New York, Abingdon Press, 1952] vol. 1, p. 890-892)
Exodus 6:26-27 These are that Aaron and Moses… these are that Moses and Aaron
Does your genealogy define who you are?  To the scribes who are inserting this section into the storyline, it is a defining characteristic: “These are that Aaron and Moses.”  In one verse, the scribe puts Aaron’s name before Moses.  In the next, out of guilt, he places Moses’ name before Aaron’s.  To the priestly scribe, genealogy means everything.  If it defines Aaron and Moses, then it defines him.  If God chose Moses and Aaron to lead the children of Israel out of Egypt, then by extension God chose the priests to lead the people in the temple sacrifices.