Then the Lord said, “Because the outcry against Sodom and Gomorrah is great and their sin is very grave, I will go down to see whether they have done altogether according to the outcry that has come to me. And if not, I will know.” - Genesis 18:20-21
From Canaan, the Canaanites descended, and their territory extended from Sidon in the direction of Gerar as far as Gaza, and in the direction of Sodom, Gomorrah, Admah, and Zeboiim as far as Lasha. (Genesis 10:15-19)
Sodom and Gomorrah and the surrounding cities indulged in sexual immortality and unnatural desire, and they serve as an example by undergoing a punishment of eternal fire. (Jude 1:7)
War of Nine Kings
Amraphel king of Shinar, Arioch king of Ellasar, Chedorlaomer king of Elam, and Tidal king of Goiim made war with Bera king of Sodom, Birsha king of Gomorrah, Shinab king of Admah, Shemeber king of Zeboiim, and the king of Bela (Zoar) in the Valley of Siddim (the Salt Sea). They had served Chedorlaomer for 12 years but rebelled in the 13th year. In the 14th year, Chedorlaomer's side defeated the Rephaim in Ashteroth-karnaim, the Zuzim in Ham, the Emim in Shaveh-kiriathaim, and the Horites in their hill country of Seir as far as El-paran on the border of the wilderness. Then they turned back for En-mishpat (Kadesh) and defeated all the country of the Amalekites and also the Amorites dwelling in Hazazon-tamar.
Then the kings of Sodom, Gomorrah, Admah, Zeboiim, and Bela (Zoar) joined battle in the Valley of Siddim with Chedorlaomer king of Elam, Tidal king of Goiim, Amraphel king of Shinar, and Arioch king of Ellasar: 4 against 5. As the kings of Sodom and Gomorrah fled, some fell into the area's many bitumen pits and the rest fled to the hill country. The enemy took all their possessions and provisions and left, including Lot and his possessions.
An escapee told Abram at the oaks of Mamre the Amorite, brother of Eshcol and Aner, all his allies. Abram led his 318 trained men in pursuit as far as Dan, dividing his forces against them by night, defeating them, and pursuing them to Hobah, north of Damascus. He brought back all the possessions and his kinsman Lot with his possessions, and the women and the people.
The Lord sets out to investigate Sodom's grave sin
The Lord appeared to Abraham by the oaks of Mamre, and the three men allowed Abraham to serve them. As he set them on their way, the Lord said, "Shall I hide from Abraham what I am about to do, seeing that Abraham shall surely become a great and mighty nation, and all the nations of the earth shall be blessed in him? For I have chosen him, that he may command his children and his household after him to keep the way of the Lord by doing righteousness and justice, so that the Lord may bring to Abraham what he has promised him.” Then the Lord said, “Because the outcry against Sodom and Gomorrah is great and their sin is very grave, I will go down to see whether they have done altogether according to the outcry that has come to me. And if not, I will know.”
The men went toward Sodom, but Abraham stood before the Lord and drew near to ask, "Will you indeed sweep away the righteous with the wicked? Suppose there are fifty righteous within the city. Will you then sweep away the place and not spare it for the fifty righteous who are in it? Far be it from you to do such a thing, to put the righteous to death with the wicked, so that the righteous fare as the wicked! Far be that from you! Shall not the Judge of all the earth do what is just?” And the Lord said, “If I find at Sodom fifty righteous in the city, I will spare the whole place for their sake.”
Abraham answered and said, “Behold, I have undertaken to speak to the Lord, I who am but dust and ashes. Suppose five of the fifty righteous are lacking. Will you destroy the whole city for lack of five?” And he said, “I will not destroy it if I find forty-five there.” Again he spoke to him and said, “Suppose forty are found there.” He answered, “For the sake of forty I will not do it.” Then he said, “Oh let not the Lord be angry, and I will speak. Suppose thirty are found there.” He answered, “I will not do it, if I find thirty there.” He said, “Behold, I have undertaken to speak to the Lord. Suppose twenty are found there.” He answered, “For the sake of twenty I will not destroy it.” Then he said, “Oh let not the Lord be angry, and I will speak again but this once. Suppose ten are found there.” He answered, “For the sake of ten I will not destroy it.” And the Lord went his way, when he had finished speaking to Abraham, and Abraham returned to his place.