Well, I have two ways of thinking about that. If we're to consider religion as something that is revealed in dispensations in the Abrahamic tradition, I think the prophets knew themselves that their words were meant for a certain age, but that people would still cling to tradition. While people might argue over the meaning of words though, The Word, that is God's Word whatever it might be is permanent and changeless, and that any changes in our areas of focus and our perception of it is due to our limited understanding and the times and situations we find ourselves in. So I don't think they worried, because in essence they know it is good, just, and true. On the other hand, we could be more mundane. The people who passed on the message were concerned with their immediate times and not much more. For example, if I vote for president I'm concerned about how it'll affect the country in the short term, not how whoever wins is gonna dictate history for the next 2,000 years.