There are no surprises on this in the Bible. For Jews, homosexual behaviour wasn’t an issue, except as part of a larger whole to which Jesus refers in traditional biblical terms. For non-Jews, such as those addressed by Paul, it was an obvious issue, since every possible kind of sexual expression was well known in cities like Corinth and Rome (there is a popular belief just now that the ancients didn’t know about lifelong same-sex relationships, but this is easily refuted by the evidence both literary and archaeological).

The danger then is that we think of things in this area as ‘rules’; for the Jew, it was a matter of living in accordance with the covenant, which was the means of God rescuing creation from the mess into which it had fallen. For Paul, it was a matter of living in accordance with the covenant that had been renewed in and through the death and resurrection of Jesus, through which God had launched his project of new creation. People often suggest that since Paul believed in grace, not law, all the old rules were swept away in a new era of ‘tolerance’, but this is a shallow and trivial view. Paul (and all early Christians known to us, right through the centuries) stuck with the Jewish view: no worship of idols, no sex outside marriage.

And marriage of course meant man/woman. There’s much more to say about this but this is for starters. I do not plan to write more about this any time soon; it’s complex and (obviously) contentious and it wouldn’t be a short book. Richard Hays’s chapter in The Moral Vision of the New Testament is still the best short treatment available.