Problem: Incest is denounced in emphatic terms in many biblical passages (cf. Lev. 18:6; 20:17). In fact, the Lord declared, “Cursed is the one who lies with his sister, the daughter of his father or the daughter of his mother” (Deut. 27:22). Yet Lot committed incest with his two daughters here, from which came the nations of Moab and Ammon.
Solution: There is no question that Lot sinned here in several ways, to say nothing of the violation of incest laws that Moses later gave as commands to Israel. Noah was drunk, and he committed adultery with his daughters. Lot’s righteous soul was vexed with many sins due to his long association with the people of Sodom. But none of these sins are approved of in this passage. Indeed, the whole colorless tone of the narrative, without any positive comment by the narrator, indicates that there was no attempt to conceal the horror of his sins. Here is a good example of the principle that not everything recorded by the Bible is approved by the Bible.