"Let’s go back to 1981. The Prophecy says I can defeat Voldy, but I’m not guaranteed to. I could die. If Dumbledore sabotages me so I fight Voldy and die, then only Dumbledore can save Wizarding Britain from Voldy’s evil, right? And thank Merlin, Dumbledore can’t possibly lose a battle to the death with Voldy, right? So Dumbledore figures that if he sabotages me to death, he’ll then defeat Voldy, and become an even bigger legend than after he defeated Grindelwald. On the other hand, if the Prophecy plays out like it seems to suggest, and I kill Voldy, then what happens to Dumbles? He becomes yesterday’s news, a has-been. To Dumbles, who cannot not be the centre of attention, this second outcome is as horrid a fate as chopping off his wand-arm. So back in 1981, beginning on Halloween, Dumbles set out to weaken me magically—by bindings on my magical core—physically—by abuse by the Dursleys—and mentally—by Ron encouraging me to skive off studying, and by Dumbles not training me."