The ancients lived in a dog-eat-dog world. Life was rougher, more violent, and generally less survivable than it is today. For many people, one of the biggest concerns was leaving a lasting legacy, both in terms of ideas and DNA. The solution? Have lots of kids. Having a big family not only meant continuity, it also meant access to labor and the ability to survive more efficiently. Oh, and bonus: it was seen as a consequence of being in with God.
The same holds for nations, not just families. Why write a book like Exodus? For fun? Not so much. The writers wanted to keep these stories fresh in people's minds so that a national identity would develop. Looks like they succeeded—and then some.
Questions About Family and Community
Why would God reward loyalty with children? What else do we know about God from Exodus that would help us answer this question?
What is the relationship between procreation and the setting of Exodus?
Which is the more important community in exodus: family or nationhood?
How do the different characters deal with the issue of continuing their lines? Is Moses concerned with continuing his family or just his nation?