This chapter is broken into two completely separate stories. The only common tie is they are both about Abraham (and god, I suppose, but that's pretty much everything in this book). First, we continue the story of Genesis 17, where god promised that Abraham and Sarah would have a son, even though they are old.
The lord appears to Abraham as three men. It doesn't specify how the lord is three different men, and it's unclear if Abraham knows who they are. He is certainly quick to offer them his best hospitality. As they're sitting around over a meal of one of his tenderest calves, one of the men asks about Sarah and says that they'll return in "due season" and she'll have a son. Sarah is listening and laughs at this, because she and Abraham are so old. She appears to be post-menopausal; at least, that's my take on "it had ceased to be with Sarah after the manner of women." I love the euphemism speak!
So then god wants to know why Sarah would laugh at that, since doesn't she know god can do anything? Except, of course, it hasn't really been established by these 3 men that they are god. So how was she to know they weren't just crazy wanderers? Anyway, now that Sarah knows it's god, she gets scared and tries to deny laughing. Aaaand scene. That's a little ominous of an ending. If this were a TV show, I'd totally be expecting Very Bad Things to come Sarah's way. But if there are, it's not in this chapter, as we now segue on to the beginning of the Sodom and Gomorrah story.
The men (who are god) are headed to Sodom, and Abraham is walking with them for a little bit because he's a good host. God has a little argument with himself about whether he should tell Abraham his plans—I guess it comes in handy to be embodied as three people when you want to talk to yourself! He ends up deciding to spill the beans. Turns out the purpose of this trip is that he's heard a great outcry about the sin of Sodom and Gomorrah and he's going to see for himself if it's as bad as all that. So, definitely no omniscience going on here. He can hear prayers, apparently, but doesn't have eyes everywhere.
Now the men split towards Sodom, but Abraham stays to talk to god. That's a little weird. Maybe the three men were totally separate from god appearing to Abraham? It's honestly impossible to tell. But now it's just god and Abraham, and they're hashing out a deal. Basically, Abraham can't believe that his god, who is just, would destroy everyone in the city if there are righteous people there. (Um, hasn't he heard of the flood?) So he gets god to agree to spare the cities if there are 50 righteous men. But then that seems to high, so basically Abraham keeps bargaining until he gets that number down to 10 righteous men. God here definitely does not come off as an omniscient, omnipotent deity of all. He's haggling with Abraham about his plans!
So now god is off to see if he can find ten righteous men in Sodom, and Abraham is presumably going back to bang Sarah so they can have that kid. Wonder how that's going to end?
2 hours ago