And the angels who did not keep their own position, but left their proper dwelling, he has kept in eternal chains in deepest darkness for the judgment of the great day. Likewise, Sodom and Gomorrah and the surrounding cities, which, in the same manner as they, indulged in sexual immorality and pursued unnatural lust,* serve as an example by undergoing a punishment of eternal fire.
* literally “went after other flesh.”
This is the most tenuous verse in connection to homosexuality. The words which are translated “pursued unnatural lust” in the NRSV – ἀπελθοῦσαι ὀπίσω σαρκὸς ἑτέρας (apelthousai opisō sarkos heteras) – literally mean “went after strange flesh.” Given the context of verse 6, the most likely intended meaning was that they sought to have sex with (or more precisely, rape) the angels.