A prophecy is made in so many different ways queen its hard to answer your question. Black people will rise is a prophecy, no? We have been saying that for so long now.... its a prophecy because it must (if not already partially) come true. Not because of any religious spiritual or spooky event... but because of a necessity for it to occur out of our current condition. Some people would then connect the metaphysical element of this..... But thats how simple a prophecy can be created and manifest. If it needs to be, masses of people require it to be, many times it will be. Eventually.
Other prophecies come about from the historical perspective. History is cyclical. Almost everything happening in the now has happened in the past. And people have been here documenting things from creation. To home in on the Bible..... if we know they had a knowledge of Ancient cultures (Suma, Kemet, India) and their histories, it wouldn't even be difficult to then extrapolate and see how certain events could take place again. Many people point to the prophecy of slavery and being 'taken in ships' back to Egypt and say look YES this MUST be a prophecy about InI ancestors that were enslaved. But again, most historians will be aware of this happening (in the exact same way) over and over. In 1000 years from now it will still be happening....
Other prophecies come about on an astrological level. Again this is something the ancestors were into. And again alludes to the cyclical nature of the stars and of nature / life itself. Many dogon or nile valley 'prophecies' were based on a cyclical timeline based on astronomy.... for example the 26000 year earth axis cycle etc. They then place spiritual value on these events. The Mayans used this to prophesize about dark ages and golden ages. This kind of prophecy is science based.
For Biblical prophecy specifically, ones should be aware of the 'Sibyls' (prophetic women). Many of them are recorded in a book entitled The Sibylline Oracles. Then if one reads The Mysteries of Osiris and Isis (Ausar / Auset) and see the VOLUME of similarities...... It then becomes easy to see how a person or Sibyl who is aware of Egyptian Mysteries could give all and more of the so called Biblical prophecies given by 'God.'
So prophecies in my opinion can come from a variety of sources. Usually based on astronomy or history; but even out of a necessity for something to happen (Jesus WILL return - the cyclical necessity for a messiah among people through history). I tried to answer staying away from the metaphysical realm which would be a whole different concept. Connecting back with ancestors, shamanism and such. I didn't include this viewpoint because the people reading and writing the bible in my opinion aren't operating on that level, and the Bible doesn't read on that level of consciousness. But that would make an interesting addition!
The whole idea of prophecy isn't that 'out there' or spooky to me.
Peace & Love