Genesis 19:38
And the younger, she also bare a son, and called his name Ben-ammi: the same is the father of the children of Ammon unto this day. And the younger, she also bare a son, and called his name Ben-ammi: the same is the father of the children of Ammon unto this day.
The younger daughter also bore a son by her own father after fleeing Sodom for the mountains, and she called his name Ben-ammi, who became the father of the Ammonites. The birth took place after Lot left Zoar for fear it would be destroyed and went to dwell in a cave in the mountains, stripped of all he had gained in Sodom. Moab and Ammon were thus the descendants of Lot and his only posterity, vile idolatrous tribes who rebelled against God and became bitter enemies of His people, which explains why the Israelites were commanded not to attack them or take their land.
The daughters' incest resulted from the corrupting influence of their associations in Sodom, whose moral corruption perverted their morals and became so interwoven with their character that it confused their sense of right and wrong and made sin not appear as sin to them, so that the curse of Sodom followed Lot even to the cave. Lot had remained so long among the wicked that he was able to save only himself and two daughters, and even they were corrupted in morals by their sojourn in Sodom. Sodom stands as a place of depraved practices that stain purity, and it was destroyed for the same corruption found among the Canaanites, including idolatry, adultery, murder, and other abhorrent practices.
The account belongs to the recorded failures of believers, showing that even men favored by God could fall into temptation and are not without faults, and it is preserved to warn and instruct later generations by teaching the consequences of sin, calling people to avoid evil and seek God's mercy, and encouraging those who struggle that through God's grace they can rise again and overcome. The verse stands as a warning to all who wish to live godly lives to separate themselves from all influences calculated to lead them away from God, and young people especially should be guarded from such practices and kept as far as possible from Sodom and its corrupting associations.