what is the sin commited by the people of Sodom and Gomorrah?

Answer 1

Gen 18:20 And the LORD said, "The outcry of Sodom and Gomorrah is indeed great, and their sin is exceedingly grave.

Gen 18:32 Then he (Abraham) said, "Oh may the Lord not be angry, and I shall speak only this once; suppose ten are found there?" And He said, "I will not destroy {it} on account of the ten."

Gen 19:1 Now the two angels came to Sodom in the evening as Lot was sitting in the gate of Sodom. When Lot saw {them,} he rose to meet them and bowed down {with his} face to the ground.

Gen 19:2 And he said, "Now behold, my lords, please turn aside into your servant's house, and spend the night, and wash your feet; then you may rise early and go on your way." They said however, "No, but we shall spend the night in the square."

Gen 19:3 Yet he urged them strongly, so they turned aside to him and entered his house; and he prepared a feast for them, and baked unleavened bread, and they ate.

Gen 19:4 Before they lay down, the men of the city, the men of Sodom, surrounded the house, both young and old, all the people from every quarter;

Gen 19:5 and they called to Lot and said to him, "Where are the men who came to you tonight? Bring them out to us that we may have relations with them."

Gen 19:6 But Lot went out to them at the doorway, and shut the door behind him,

Gen 19:7 and said, "Please, my brothers, do not act wickedly.

Answer 2

4 Before they had gone to bed, all the men from every part of the city of Sodom--both young and old--surrounded the house.
5 They called to Lot, "Where are the men who came to you tonight? Bring them out to us so that we can have sex with them."