St Paul's letter to the Romans is frequently cited as opposition to marriage rights for gay people. Of course, since the modern concept of homosexuality did not exist in St Paul's time, let alone a modern concept of marriage, it's pretty clear St Paul was speaking of abusive and promiscuous sexual acts, not faithfully committed monogamous relationships. In fact, in our own time, he might have been a supporter.
Jonathan Rauch writes,
Paul? How can that be? Doesn’t he condemn homosexuality famously and in strong terms?...
In “Paul Among the People,” Sarah Ruden, a classical translator and scholar, uses ancient sources to look at Paul as he would have been seen in his own time and context. ...By the standards of his day, Paul was a progressive social reformer.
....No one in Paul’s day had any inkling of a loving, consensual homosexual relationship. “There were no gay households; there were in fact no gay institutions or gay culture at all,” writes Ruden. “The only satisfying use of an adult passive homosexual was alleged to be oral or anal rape — the satisfaction needed to be violent, not erotic.”
Roman mores of Paul’s day regarded male-male intercourse as an act not of love but of domination....Because families with social standing took pains to guard their children, “predators naturally turned to those with no protectors, young male slaves and prostitutes,” writes Ruden. “An adult could exploit an abused slave child’s loneliness and humiliation again and again.”
...This was the context in which Paul condemned “unnatural acts” as “wickedness.” Where others before him had condemned only the passive partner, he condemned both. “He makes no distinction between active and passive: the whole transaction is wrong.” In his time, his teaching would have been ethically innovative, a blow against sexual relations that were at best grossly unequal and that often amounted to what we would today call sexual abuse or rape.
...And if his aim was to replace sexual domination, coercion and exploitation with mutuality, consent and caring, then same-sex marriage is a logical step along the path he opened. Someone with Paul’s values who is around today might look at caring and committed gay couples and conclude that there is an honored place for their love within the church, and indeed within marriage.Cue fundy heads exploding!