This chapter has significance in all Judaeo-Christian religions because of the reference to homosexuality, and that it is an “abomination” to the extent that God destroyed these cities as a result of this verse:
Where are the men which came in to thee this night? bring them out unto us, that we may know them. And Lot went out at the door unto them, and shut the door after him, And said, I pray you, brethren, do not so wickedly. Behold now, I have two daughters which have not known man; let me, I pray you, bring them out unto you, and do ye to them as is good in your eyes: only unto these men do nothing; for therefore came they under the shadow of my roof. Genesis 19: 5-6
The angels who had appeared to Abraham, travelled to Sodom, arriving at Lot’s house in the evening. Lot is hospitable, offers them a place to stay for the night. They refuse the offer, saying they’ll sleep in the street, but he insists and they accept his invitation to have a meal and stay the night (verse 3).
The men of Sodom surround the house, demanding that he send them out “that we many know them”. Lot offers his daughters instead.
When the men insist that they want the visitors, Lot goes out to reason with them, but the angels pull him back, and smite the men of Sodom with blindness (verse 11).
The angels ask Lot about his family, sons, daughters, sons-in-law, saying that they should be sent from the city, because God has sent them to destroy it. In the morning, the angels insist that Lot and his family leave the city, telling him to “escape for thy life, look not behind thee, neither stay in the plain; escape to the mountain, lest thy be consumed.” (verse 17).
Lot pleads with the angels to allow him to escape to the “small city” which is called “Zoar”. The angels agree that he should escape there while they destroy Sodom and Gomorrah, raining down “brimstone and fire” on them (verses 18-25).
Lot’s wife looks back to see the destruction, and is turned into a pillar of salt (verse 26).
Abraham wakes up to see the destruction happening to the “cities of the plain” while God sends Lot away from Zoar to hide in the mountains, with his two remaining daughters.
In the following verses, 31 to 38, the writer explains the origins of the Moabites and the Ammonites. The two daughters cause their father, Lot, to become drunk. They seduce him in order to have children because they believe that all the eligible young men in their little world have been killed.
There are three purposes in this mythology being included in the Old Testament. The first is the obvious one: the condemnation of homosexuality. The phenomenon of homosexuality must have been fairly common among the people of Canaan, perhaps all civilisations noticed the behaviour among their members, however, only the people who claim to be descended from Abraham make a fuss about it. That they do this, says more about their obsession with sex, than it does about same gender sexual attraction. See the Wikipedia article linked to here.
The Greeks were at ease about both homosexuality and nudity, and the Romans, although they were a little more conservative in their public sexual behaviour, nevertheless had several famous characters who were gay. See full quote here.
As has been frequently noted, the ancient Greeks did not have terms or concepts that correspond to the contemporary dichotomy of ‘heterosexual’ and ‘homosexual’. There is a wealth of material from ancient Greece pertinent to issues of sexuality, ranging from dialogues of Plato, such as the Symposium, to plays by Aristophanes, and Greek artwork and vases…Probably the most frequent assumption of sexual orientation is that persons can respond erotically to beauty in either sex… For example, Alexander the Great and the founder of Stoicism, Zeno of Citium, were known for their exclusive interest in boys and other men. Such persons, however, are generally portrayed as the exception…
From the Wikipedia article on homosexuality in Rome, there is the following:
It was expected and socially acceptable for a freeborn Roman man to want sex with both female and male partners, as long as he took the penetrative role. The morality of the behavior depended on the social standing of the partner, not gender per se. Both women and young men were considered normal objects of desire, but outside marriage a man was supposed to act on his desires only with slaves, prostitutes (who were often slaves), and the infames (people with little or no social standing). Gender did not determine whether a sexual partner was acceptable, as long as a man's enjoyment did not encroach on another man's integrity. It was immoral to have sex with another freeborn man's wife, his marriageable daughter, his underage son, or with the man himself; sexual use of another man's slave was subject to the owner's permission…In the Imperial era, anxieties about the loss of political liberty and the subordination of the citizen to the emperor were expressed by a perceived increase in voluntary passive homosexual behavior among free men, accompanied by a documentable increase in the execution and corporal punishment of citizens.
The people of the Old Testament even included prohibition of it in their laws, with extreme punishment for the behaviour, as may be seen from the laws of Leviticus (18:22), and the fact that until the 21st century, homosexual acts were, and in some cases still are, a crime.
The mythology of the destruction of the cities of Sodom and Gomorrah seems to have been placed in Genesis to lay the foundation for the condemnation of the behaviour. There is another example of this subject in further mythology, notably in Judges 19.
The next reason for the story is to place the historical origins of the Ammonites and the Moabites, and the third one to point out that they were descended from the incestuous coupling of Lot and his daughters, and thereby to lay the foundation for the laws that prohibit father and daughter incest, again in Leviticus (18: 6-29).
The Ammonites and the Moabites, although they are descended from Terah, the ancestor of Abraham, and thereby, from Noah, are not allowed to intermarry with the Hebrews because they are descended from incest. Making them the sons of Lot with his daughters, makes the prohibition valid.
The two states, Ammon and Moab, were historically real (see map on this Wikipedia page)
The chief city of the country [Ammon] was Rabbah or Rabbath Ammon, site of the modern city of Amman, Jordan's capital. Milcom and Molech (who may be one and the same) are named in the Bible as the gods of Ammon. The people of this kingdom are called "Children of Ammon" or “Ammonites.”Also note the origins of David:
The Ammonites presented a serious problem to the Pharisees because many marriages with Ammonite (and Moabite) wives had taken place in the days of Nehemiah. The men had married women of the various nations without conversion, which made the children not Jewish [even though they were descended from the same ancestral line]. The legitimacy of David's claim to royalty was disputed on account of his descent from Ruth, the Moabite.
The Moabites, as may be seen from this Wikipedia quote, were also people of the area we now refer to as Jordan.
Moab… is the historical name for a mountainous strip of land in Jordan. The land lies alongside much of the eastern shore of the Dead Sea. The existence of the Kingdom of Moab is attested to by numerous archeological findings,… capital was Dibon. According to the Bible, Moab was often in conflict with its Israelite neighbours to the west.
I do not dispute the existence of the actual lands, or peoples, of the area in which the bible story is set. I merely refute the truth of the historical account, which is obviously a repeating of the oral tradition, handed down through the centuries, until the writers put it down on parchment, calling it the “history of the Jewish people.” This story is no more real history than any other mythological origin story told around campfires in the early days of any civilisation.