Exodus has a bit of everything, from thrilling fire and brimstone stories to (we'll admit it) super-boring legal text.
Put it all together, and we get a taste of everything a new society needs to function: stories on which to base national pride (we were freed from Egypt by God!); laws (and laws…and laws); and hey, why not some poetry to top it all off?
Remember that all of these layers don't necessarily come from the same writer, or even the same era. Let's take a look:
7:22-25: The writers talk about the plagues hitting the Egyptians and not the Israelites. Do the Israelites live in a separate land next to the Egyptians?
Chapter 14: The writer states that 600,000 men plus women and children left Egypt. Um, wow. Aside from being a crazy big number, it seems to contradict the population implications earlier in the story—how could 2 midwives deal with 600,000+ people?
Chapter 15: When the Israelites thank God for helping them across the Red Sea, they sing about conquering Canaan before it's happened. Anachronism, anyone?
Chapters 25-31 and 35-40: We interrupt this super exciting Ten Commandments drama to bring you… the blueprints of the Tabernacle? Hmmm.
Bottom line: you can't write the entire history of a people in a day. And when you piece bits together, you're bound to get some idiosyncrasies. But what's a good story without some idiosyncrasies?