Usually there is one or more ways so-called “prophecies” in the Bible can be explained…
(1) The prophecy is vague enough that you can read whatever you want into it (e.g.: “a three-headed lion will appear in the east”). One person may claim it means one thing, and someone else may claim it means another.
(2) It’s a “prophecy” about things that happen all the time, so there’s nothing special about it. For example, “There will be wars and rumors of wars in those days,” floods and earthquakes, etc.
(3) It isn’t a prophecy in the first place, or it isn’t a prophecy about what it’s claimed to be about. A closer reading of the passage in context will usually expose these types of “prophecies.”
(4) If the prophecy is known, then someone who knows it might be motivated to fulfill it. For example, if I know that the hero is supposed to ride a white horse–and I want to appear to be the hero—then I could start looking for a white horse to ride.
(5) The prophecy is manufactured after-the-fact to fit what happened. If I say, “so-and-so happened to fulfill such-and-such a prophecy,” I might be making up the prophecy.
(6) The story is manufactured after-the-fact to fit the prophecy. If I’m writing a story about someone’s life and know about some prophecy that should apply to that person, I can just make up a story that it happened, even if it didn’t.
Let me take the so-called “prophecy” about Jesus from Zechariah 9:9 as it was relayed by Matthew to use as a general example (where more than one of the above may apply)….
Here is the text, “Rejoice greatly, O daughter of Zion! Shout in triumph, O daughter of Jerusalem! Behold, your king is coming to you; He is just and endowed with salvation, Humble, and mounted on a donkey, Even on a colt, the foal of a donkey.” First, it’s fairly vague. It doesn’t specify who the “king” is or when he will come exactly. And how many people probably rode into Jerusalem on a donkey every day? Obviously, not everyone riding in on a donkey would be the king, so there’s nothing here to link Jesus specifically with this passage (and he wasn’t a “king” in the way intended anyway). So, it’s vague, it cites something that happened all the time (humble people riding donkeys into the city), and it may not be a prophecy about what it’s claimed to be about (since a different type of “king” was probably intended than the one Christians claim Jesus was). That covers 1-3 above.
If Jesus was aware of this “prophecy,” then he could have easily acquired a donkey to ride in on (if he was trying to “sell” himself as the “king” Zechariah mentions), so there would be nothing amazing about that. Finally, Matthew clearly misreads the “prophecy” and has Jesus riding into Jerusalem on TWO donkeys! [The passage is saying the donkey is a colt, not that there were two different donkeys.] So Matthew is pretty clearly manufacturing a story after-the-fact to fit the prophecy as he misunderstood it. His mistake revels he was making stuff up. So, that now also covers 4 & 6 above. Note: of all the Gospels, Matthew seems to go to greater lengths to manufacture stories to fit “prophecies” than the other three.
I think all of the so-called “prophecies” in the Bible can be explained by one or more of the ways I listed above. It’s just a matter of looking into any of them more closely with these possibilities in mind.
A Side Note
Some Christian apologetics make the argument that “any prophecy made about the Messiah that was not fulfilled in Jesus simply refers to his second coming.” This is how some respond when confronted with what was actually prophesied a “Messiah” was going to accomplish that Jesus didn’t accomplish.
There’s a book I read in 1998 called “The Mythmaker – Paul and the Invention of Christianity” by a Talmudic scholar Hyam Maccoby which addresses some of this from the Jewish point-of-view. Maccoby argues that Jesus regarded himself as the Messiah in the normal Jewish sense of the term, i.e. “A human leader who would restore the Jewish monarchy, drive out the Roman invaders, set up an independent Jewish state, and inaugurate an era of peace, justice and prosperity,” and that “Jesus believed himself to be the figure prophesied in the Hebrew Bible who would do all these things.” And prophecies like these are exactly what Jesus didn’t accomplish, which is why Jews don’t recognize Jesus as a Messiah.
He says Jesus believed that God would perform a great miracle that would take place on the Mount of Olives, as prophesied in the book of Zechariah. He says that “When this miracle did not occur, his mission had failed. He had no intention of being crucified in order to save mankind from eternal damnation by his sacrifice. He never regarded himself as a divine being, and would have regarded such an idea as pagan and idolatrous, an infringement of the first of the Ten Commandments.”
He says that the phrases “Son of Man” and “Son of God” were things that any Jew might say about himself because they all considered God their “Father,” and Jesus wasn’t making any special claim for himself by referring to himself that way. It was something any Jew might do.
As you may know, ‘Christ’ was the Greek alternative for the word ‘Messiah’ and Maccoby argues that the terms didn’t imply someone divine aspect (he says, “every Jewish king of the Davidic dynasty had this title”), but it was Paul who was the person who made it into something more than what the term originally meant, or what Jesus might have considered it to mean. Maccoby claims Jesus would have been shocked by what Paul did.