Chapter 4 doesn’t mention the Arahamic Covenant or Isaiah at all; so what’s its place in the record besides the story? Well, I think Nephi’s comparison of their situation to the children if Israel is significant. I think Nephi is not just using the story to say that big, miraculous things have happened once so they could potentially happen again — I think Nephi is trying to say that they are the children of Israel, just like Moses’s people were. I think he’s trying to get his brothers to really inhabit that idea, that position in relation to God. Jerusalem has become wicked, just like Egypt; Laban won’t let us go with the plates so we can worship God, just like Pharaoh wouldn’t let the Israelites go to worship God; we won’t be able to make it through this without miracles, just like the Israelites. God has chosen them out — an angel just spoke to them! — and that entitles them to certain blessings as they fulfill God’s commandments. They are a chosen people.
I think verses 14-15 are the most significant to this project. Lehi reads that they are descendants not just of Israel generally but of Joseph specifically. Right away, Nephi points out that, “yea, even that Joseph who was the son of Jacob, who was sold into Egypt, and who was preserved by the hand of the Lord, that he might preserve his father, Jacob, and all his household from perishing with famine. And they were also led out of captivity and out of the land of Egypt, by that same God who had preserved them.” Nephi doesn’t draw any parallels here but it does set up some ideas that will be fleshed out later on. Lehi is like Joseph, leaving the rest of Israel’s family so that he might preserve the whole of Israel in some future time.
Again chapter 6 doesn’t have a lot, but Nephi does mention Abraham in verse 4: “For the fulness of mine intent is that I may persuade men to come unto the God of Abraham, and the God of Isaac, and the God of Jacob, and be saved.” Nephi could have used many different titles for God, and I think it is significant that he used this one.
I don’t see much here. A few small things, maybe. Maybe the story of Laman & Lemuel’s rebellion and then Nephi’s forgiveness is supposed to echo God’s forgiveness, but that’s unclear. I think it’s more to show that God’s mercy and power was with Nephi, and for the blessings the faithful receive to keep fulfilling God’s commandments. (I think.)