The special creationist claim that Cain and Seth married their sisters not only is a classic example of how fundamentalists forces the Bible into conflict with scientific facts (in this case the fact that the human race never was any smaller than several thousand people), but more importantly, as Biblical scholar Tim Bulkeley notes, the fundamentalist assumption that the narratives are mean to be read in a flat, literal manner as if written by 21st century historians for 21st century readers are asking the wrong question of the narratives.
Bulkely wisely notes that apart from 'address[ing] the wrong question', the glib answer to the problem of where Cain obtain his wife positively creates problems:
Noticing other awkwardnesses in the story may actually help us see it more clearly. Back in v. 2 we read, “Abel was a keeper of sheep, and Cain a tiller of the ground.” These descriptions imply distinct ‘jobs.’ That sort of specialisation would hardly happen when there were only four humans on earth. The teller of the story is thinking and speaking of the world they (and we) live in, not the world of Cain and Abel.
Further on, Cain is worried that when he wanders, “anyone who meets [him] may kill [him].” If there are only three humans left alive then surely the more he wanders the less chance of him meeting anyone. Either the telling of the story is inaccurate, or the teller is not concerned with such details but has their eye on another goal.
There is a powerful clue for us. Quibbling about where Cain's wife came from is a waste of time, because it misses the point of the Bible passage. Many ‘Bible difficulties’ are like this; they are only an issue if we try to get information from Scripture that the author was not interested in providing.
To a first approximation, if we approach the early chapters asking 'why' and not 'how', we will go a long way to avoiding the problems that YEC creates by imposing the wrong interpretive framework on the text.
Full article is here.
