Genesis 19:31
And the firstborn said unto the younger, Our father is old, and there is not a man in the earth to come in unto us after the manner of all the earth: And the firstborn said unto the younger, Our father is old, and there is not a man in the earth to come in unto us after the manner of all the earth:
The verse records the proposal of Lot's firstborn daughter after Lot had left Zoar for the mountains to dwell in a cave, stripped of all for which he had risked his family in a wicked city, reasoning that their father was old and that no men remained to continue the family line in the manner of all the earth, and then acting upon that reasoning in a sinful way. That sinful conduct after leaving Sodom came from evil association there, whose moral corruption had corrupted their morals and become interwoven with character until the sense of right and wrong was confused, good and evil could no longer be distinguished, and sin no longer appeared as sin to them. The only posterity of Lot from that act were the Moabites and Ammonites, vile and idolatrous tribes, rebels against God and bitter enemies of His people.
The passage stands in the honest record of the failings of people favored by God and of Bible believers, showing that even faithful persons can fall. It is preserved as warning and instruction that others may be warned against sin and avoid such evils, while the account of struggle and recovery through God's grace encourages others to keep resisting evil. As part of the account of Sodom, a place marked by depraved practices, it warns that exposure to such corruption can stain the soul, so youth should be guarded from it and kept as far as possible from Sodom-like places and associations. Joined to the destruction of Sodom, in which only very few were saved though warned, it illustrates that the majority may perish and that numbers do not determine who is right.