What does Genesis 19:31 mean?

Though saved from the destruction of Sodom and Gomorrah, Lot and his two grown daughters have lost everything else, including Lot's wife, the girls' mother. They've been reduced to living in a cave in the hills, overlooking the annihilation of the entire region.

Prior to these events, Lot's two daughters had been engaged to men in Sodom (Genesis 19:14). Those men were destroyed along with the rest of the city for their wickedness. Now they cannot imagine a life beyond what they have lost. From their perspective, they will find no husbands. They will never have children. Some interpreters speculate that Lot's daughters might have believed they were the only people left on earth. Others think it's more likely these women felt that men from outside their familiar culture were unsuitable as husbands.

The following verses will reveal the actions they choose to take in response to their view of the world, but it is important for us to recognize that their view is false. Though they could not see it then, the world beyond what was lost was still full of eligible husbands. The God who had so dramatically saved their lives would certainly be capable of providing husbands for them in due time. Clearly, Lot also did not lead them to this conclusion, though he apparently had no idea what they had planned for him.

Lot's daughters were not willing or able to trust God in this, however. Given that they were raised in the depraved culture of Sodom, and engaged by their father to men of that city, this is hardly a surprise.