The longest part of this chapter is the song of Moses followed by a brief section of Israel's wanderings in the desert. I will discuss the material in that order.
The first thing I want to say about the song of Moses is that it is structurally poetic. This is typical of basically all songs in the OT. The Psalms, for instance, were generally intended to be sung and even include musical cues in the text, but they also follow the poetic structures that I laid out previously in Genesis 49, even though that was a prophetic section while this is musical. We see many instances here of what I call thematic parallelism, where consecutive lines say the same thing in different ways. I don't believe I'm going to discuss the literary structure of the song anymore because while it is very beautiful, I want to focus more on the content.
With that in mind, it is clear that this song can help us see how the Israelites and the author of Exodus would have viewed the crossing of the Red Sea.
The song of Moses is essentially a poetic recapitulation of the crossing of the Red Sea. It describes in very florid terms how the Israelites view the destruction of the Egyptians. There are a couple key ideas that are expressed: 1) the LORD overthrew the Egyptians with great strength, 2) "the LORD is a warrior", 3) the Egyptians "rise up against [the LORD]", 4) the LORD redeemed the Israelites, i.e. brought them out of Egypt, 5) the various peoples of Canaan are disturbed by reports of the crossing of the Sea, 6) the LORD is bringing his people to the promised land, which is variously called "your holy habitation", "the mountain of your inheritance", "the place... which you have made for your dwelling", "the sanctuary."
Some of these elements are essentially synonymous with points I have raised before. For instance, I repeatedly highlighted the dichotomy between the LORD and Pharaoh, that Pharaoh was essentially challenging the LORD and not Israel. This song shows that the Israelites viewed it that way as well, because they considered the LORD's retribution to be his wrath against "those who rise up against you". The majority of the references emphasize the strength and power of the LORD in his destruction of the Egyptians, which I also mentioned starting around Exodus 3, when I said the new manifestation of the LORD was emphasizing his miraculous powers and sovereign dominion over the earth.
We can see a few novel dimensions as well, such as the foreshadowing of their arrival in Canaan. This was only briefly mentioned during the exodus story, but now that the Israelites are out of Egypt, it appears that their minds are turning to their destination, the promised land. We see this through the statements about the fear of the Canaanite peoples and through the various descriptions of the promised land itself. While chronologically the Canaanites had not yet heard of the crossing, this song predicts their response (or alternatively, one could say this is an anachronism). I already stated that one of the purposes of the plagues of Egypt and the splitting of the Sea was to spread the LORD's reputation around the world, but a side effect of this is to intimidate the Israelite's enemies, such as the peoples living in the land they are heading to occupy. However, remember that this is a poetic section so really what's being said here is that the Israelites are rejoicing in the fear that their enemies have regarding the LORD. We will later see the Canaanites' response to the Israelites when they enter the promised land.
Next, I think some of the language describing the promised land is very interesting. The common theme is that God is leading the Israelites to the land where God dwells. This is certainly new and was not contained in any of the promises given to the patriarchs. In my opinion that's partially because the promised land as a concept was never established in the first place. In some respects it's almost hard to figure out why Abraham and his children would value the promised land so much given that they had no prior attachment to the land. At the time I was busy speculating about the cultural significance, but we don't really know much about what Abraham thought of the promised land other than his obvious enthusiasm for it. After Abraham, to all of his descendants the promised land has been chiefly defined as "that thing God gave us" so valuing the promised land is roughly equivalent to valuing the gift giver. I, for one, am glad that we're finally seeing a better definition of what the promised land means to the Israelites and here that definition is clear: the promised land is where God dwells.
We know that God dwells in the heavens, but here it says that the promised land, is where God dwells. I believe this establishes a duality between the abiding presence of God in the Israelite's immediate promised land and the vaguer dwelling of God in heaven, which by transference becomes a "promised land in the sky." To be more specific, since the song equates God's dwelling place with the promised land, one can either extrapolate God down and say that God will dwell in the physical promised land, Canaan, or extrapolate the promised land up and say that God's heavenly dwelling is somehow a "great promised land in the sky" to which all of the Israelites are headed in some sort of mystical journey. Since I've already demonstrated that the plagues of Egypt correspond with the Genesis 3 death, I think a mystical interpretation of this song is reasonable. The mystical or metaphorical interpretations is further supported by the poetic language of this chapter.
To be sure, we have seen very little so far that discusses God's dwelling place, how that relates to humanity, or how any of these things fit together. A thoughtful reader might criticize me for making such loaded statements as "God's heavenly dwelling is Israel's destination" when we have been told almost nothing about heaven or how it makes sense for people to go there (even in a mystical sense, much less a literalist one). To such critics, I would only say that this chapter establishes the promised land, the destination of the Hebrews' journey, to be where God dwells. This is another massive reversal of the curse of Adam, which saw Adam and Eve ejected from the garden of Eden, the past dwelling of God on earth. Having established their protection from the death of Genesis 3, we now see the reversal of the exile of Genesis 3. For this construction, the specific nature of heaven or exactly what it means to abide with God is ultimately not material. These are questions we can answer in more detail when more detail is given us.
We also see a rare reference to the wrath or anger of God. We have seen God do a lot of things but he has never been described as particularly angry (there was a small reference in Exodus 4:14, maybe a few others). So much of what we have seen is either the actions or the words of the LORD and not much of what other people have to say about the LORD. Additionally, all poetic sections contain an abundance of hyperbole and metaphors that is not found in any other type of biblical literature. I have said before that the language of the bible is typically very muted and especially understates the emotional nature of some events; the poetic sections of the bible are an exception to this. Not only is the language more vivid, but the topics of poetic literature are frequently emotional which is something not often covered by historical, legal or other texts in the bible. Prophetic texts use a poetic style, but they also do not usually use emotional language (some exceptions apply).
I will discuss the topic of God's anger later, just note that the pattern describing God's anger is substantially reused in later poetic literature: burning anger, fire consuming chaff, and blast of the nostrils.
"The LORD is a warrior". I highlighted this verse because it foreshadows the LORD as warrior trope of the book of Joshua. I will return to this subject as well.
In verses 20-21 the women "answer" the men's song with dancing and singing. This call-response musical style is called antiphony. This is something we see several times in the Pentateuch and elsewhere in the OT (for instance, Psalm 136 is clearly antiphonal). It was also popular in medieval church music, but has since declined somewhat. Here, the women are singing the response portion, which possibly would have been interleaved throughout the main chorus since that's how antiphony usually works. I don't think this has any particular theological significance, but it should help give the reader a sense of the culture of the time.
The presence of the cloud of smoke and pillar of fire signifies a new era in the LORD's relationship with Israel, as I previously alluded. The first reference to this manifestation is in Exodus 13, after the departure from Egypt had begun, and it continued to have an influence in protecting the Israelites from their Egyptian pursuers in Exodus 14, and now in Exodus 15 we properly begin the next section of the Israelite journey: the journey through the wilderness.
I discussed some of the peculiarities of the crossing of the Red Sea in the last chapter, how it seems out of place with the exodus story and the plagues. One reason is the detailed descriptions of the festival, consecration of the firstborn and other various ceremonies which serves as a conclusion to the exodus account and textually separates it from the crossing. Another reason why I think it is logically distinct from the plagues of Egypt is because of the placement of the pillar of cloud and pillar of fire in Exodus 13:21-22. This manifestation first appears in Exodus 13 but it is absolutely iconic of the next lengthy period of Israel's wanderings, which roughly encompasses the rest of Exodus and the next 3 books (Leviticus through Deuteronomy). In this fashion, the crossing of the Red Sea is actually grouped together with the journey through the wilderness and not the exodus from slavery in Egypt. What makes this questionable is that the crossing of the Red Sea is also defined by the antagonism of Pharaoh, which is definitely characteristic of the exodus and not the wanderings. So in these ways the crossing of the Red Sea appears to take on a few characteristics of the exodus (antagonism of Pharaoh) and some characteristics of the wilderness journey (protection of the pillars) and some characteristics that do not appear in either (symbolic of baptism? A separation from the worldliness of Egypt?). So it's almost like a transition between the two, yet it is far too long to be regarded as a simple transition. For instance, the transition between Genesis and Exodus is approximately contained in Exodus 1:1-6 which is extremely short and doesn't have any meaningful content. As I've described, the crossing of the Red Sea doesn't really fit into either story arc, so it's kinda like a story in itself, yet one that merges elements from what is before and after it.
Note that while chapter 15 (the subject of this discussion) does not mention the pillar of smoke and fire, the text in Exodus 13 implies that it is present every day with them and we will see later references to the pillars guiding Israel, so I believe it is clear that the pillars are still present with Israel during the events in this chapter and all of the chapters that follow in the book of Exodus. This leaves the entire Israelite community with an everpresent reminder of the protection and provision that the LORD provides to them. As we will see, provision repeatedly becomes a critical issues because they are traveling through a desert which has very little food or water. This new manifestation therefore shows us how God is trying to reveal himself both to the Israelites of that day but also to us in modern life as the everpresent help, the God who fulfills our needs when we live in a place where we cannot provide for ourselves.
In this chapter we see another iconic trait of Israel's wanderings, which is the constant complaining and grumbling of the people. We also saw this in Exodus 14:10-12 and I laughed about it at the time because the language was so sarcastic, but a thoughtful reader will notice that this is another characteristic of the wilderness journey which has seeped into the account of the Crossing and it reinforces the point I made above about the many peculiarities of the Crossing. While it's true there was some complaining in the exodus account (in particular, around Exodus 5:21), I do not believe that it defines Israel's behavior during that time period. In fact, during most of the plagues, the people of Israel were not really an actor in the story at all. They are referenced a handful of times, but usually in a passive sense like, "the plague did not strike Goshen or harm any Israelite". Other times the Israelites are just doing what Moses told them. Here, beginning in Exodus 14 and continuing on through this chapter, we see the Israelite people become more involved in the story where they seem to be predominantly defined by their 1) neediness, 2) complaints or threats against Moses. We will see the descriptions of Israel steadily change for the worse as the story progresses, but for a little while it's mostly just complaining and their general helplessness. While I think the life of Moses is fascinating and very instructive, I am also deeply interested in the interplay between God and the Israelite people. One can also observe the differences in how God presents himself to the Israelites in general and Moses in particular. I encourage my readers to pay attention to how the LORD interacts with the Israelites (what he gives them and speaks to them through Moses) and how the LORD interacts with Moses himself. I will try to note any similarities or differences in how God interacts with these various parties throughout Exodus.
Israel's journey through the wilderness begins at Marah with "bitter" (i.e. salty or alkaline) water, which required supernatural intervention to make it clean and drinkable. This is the first time we hear the LORD described as a healer even though he isn't exactly healing a person in the way that word has come to mean. I believe it's a reference to "healing" the water of its saltiness, but verse 26 also directly connects it with their supernatural protection from the plagues of Egypt. In that case, I said that the Israelites were protected from God's judgment under the Goshen principle, but in this case, we see that this divine protection also includes divine restoration. This implies that both healing (i.e. restoration) and protection are part of the Abrahamic Covenant. I didn't expect that turning saltwater fresh would be part of the healing and restoration package, since I didn't think saltwater is part of the curse of Adam, yet perhaps it is.
Before, the Goshen principle was (loosely) tied to a sacrifice of atonement; here, restoration is tied to Israel's obedience to the covenant. This obedience appears to be their weakpoint, as the Israelite people are already chafing under the LORD's leadership.