DS9 "Prophet Motive" (Prophets speaking to Quark):
ROM: (quarters) Did the Sisko send you?
QUARK: What? Sisko? What does he have to do with anything?
SISKO: (office) The Sisko taught us about corporeal lifeforms.
KIRA: (Promenade) About linguistic communication.
BASHIR: (Infirmary) And linear time.
QUARK: I know all about it. He's quite a guy. But I'm not here to talk about Sisko.
KIRA: All right, how about this? The Prophets, the aliens who live in the wormhole as you call them, exist outside of linear time. They know the past, present, and the future.
KIRA: It seems perfectly reasonable that they could've communicated knowledge of the future to a Bajoran named Trakor. He wrote down that knowledge in the form of a prophecy and now, three thousand years later, we are seeing those events unfold. To me, that reasoning sounds concrete, solid, I'd even call it Starfleet.
I know the above dialogue is only speculation on Kira's part but by the end of the episode it's clear, at least by the characters, that the prophecy was correct and 3000 years old.
SISKO: It's almost like the wormhole was wedged open just a crack. Just enough to let subspace signals through.
KIRA: The prophecy came true. All of it. We just misinterpreted Trakor's words. The three vipers. He wasn't talking about the Cardassians. He meant the three comet fragments.
SISKO: The communications relay. In a sense we've been trying to peer through the temple gates.
KIRA: The silithium ignited the wormhole, burning the temple gates.
SISKO: So that they never close again.
KIRA: And it's all because the Emissary used the Sword of Stars.
SISKO: And Trakor saw it all three thousand years ago.
And then afterwards Sisko wants to know about the next prophecy. DS9 "Destiny":
YARKA: Perhaps so. There are signs that Trakor's fourth prophecy will soon come to pass as well.
SISKO: Don't tell me that has something to do with me?
YARKA: You, Commander? Well, it is a prophecy about the Emissary.
SISKO: Tell me about it.
YARKA: The fourth prophecy says that the Emissary will face a fiery trial and he'll be forced to choose
From this we could deduce that Trakor had communicated with the prophets at some point 3000 years ago.
We also learn that the "prophets" were originally Bajorans that discovered the orbs many years before and transformed, at least I think that's correct. So they were originally linear corporeal beings.
I'm confused at how Sisko could be the first corporeal being they've encountered when they themselves were linear/corporal before their transformation. And I'm confused at how there could be so many prophecies from the prophets if they haven't encountered anyone before Sisko and don't understand the concept of linear time. I'm also confused at how you write a prophecy without understanding linguistic communication? Was Sisko really the first linear/corporeal being that they encountered?