I have discussed the contingent nature of biblical prophecies and promises, even those without explicit contingencies, a few times on this blog and elsewhere, including:
A few years ago, James Stutz and I helped Stephen Smoot research a paper in response to The Bible vs. Joseph Smith that went into some detail, too, about the contingent nature of biblical predictions:
A classical text for such is Ezek 26 and the promised (but failed) destruction of Tyre. Recently, Dr Joshua Bowen has posted a youtube video interacting with, and critiquing an attempted response by a popular (and very errant) Evangelical Protestant apologist on this issue:
