If you actually look at the prophets of the Hebrew Scriptures/Old Testament, prophecy is not really about telling the future. It’s about telling the present. A prophet is someone who tells it like it is, who says the things others won’t say and gives no thought to whom they might offend.
Trump actually says nothing that other Republican candidates haven’t already implicitly said. He might say it more outrageously, in a manner that grabs the attention of the media more forcibly, but there’s essentially nothing in his rhetoric that wasn’t there already.
In other words Trump’s dogma, with all its bigotry and selfishness and cruelty, is all already there, latent, in the kind of right wing ideology many in the GOP espouse. But it’s Trump who puts the writing on the wall (that’s imagery borrowed from the Old Testament too – see Daniel 5) for everyone to see. Trump’s rants are simply what extreme right-wing principles look like when they’re not dressed up all pretty with euphemisms and clever speech writing.
So let us give thanks for Trump. He’s the prophet who is making explicit what we’re really dealing with here. It’s ugly, but it’s not hidden any more, and if it’s not hidden then it will hopefully be easier to fight.