Voldemort talks about a power to vanquish him in GoF

[lily_paige_delaney]

No: HPFGUIDX 76008

Now that we know about the prophecy does Voldemort's address to the 
Death Eaters at the end of GoF make sense.

Specifically (Ch 33 The Deathe Eaters, pg 562)when Voldemort asks why 
they never came to his aid.

"...And I answer myself, perhaps they belived a still-greater power 
could exist, one that could vanquish even Lord Voldemort...perhaps 
they now pay alligiance to another...perhaps that champion of 
commoners, of Mudbloods and Muggles, Albus Dumbledore..."

This is quite confusing because if Voldemort heard the first part of 
the prophecy he knew that the "one with the power to vanquish the 
Dark Lord" would be born at the end of July etc etc.

Then, at the end of the chapter, Voldemort says (pg 571)

"You see, I think how foolish it was to suppose that this boy could 
ever have been stronger than me..."

So he clearly wants to prove that he is stronger than Harry but is 
this just because of the attack when he was a baby or because of the 
prophecy?

What this all means I have no idea but I would really like to know - 
why is Dumbledore the only one he ever feared?  And what is 
Dumbledore's relationship to Harry - because there must be one.

LPD