This is not to say we should not belive something because "that's what they would have said then" but rather we should not take something ment for a specific person or group as being ment for everyone.

By that reasoning you can take most of Paul's writings and ignore them as they were letters aimed at very specific groups of people.

Also, didn't Christ specifically say that he didn't come to replace the Jewish law, implying that you should still be paying attention to the Old Testament ?

P.S. does anyone know of a verse in the Bible that forbids sex before marriage ? I always hear Christians (usually taking to teenagers) saying that the bible outlaws sex before marriage, but I have yet to find one that provided any evidence that this is true. I spent a long time looking for such a verse when I was a 17 year old Christian... (I'm not a Christian anymore)