“I have been sure that he would try, ever since your wand beat Voldemort’s in the graveyard of Little Hangleton. At first, he was afraid that you had conquered him by superior skill. Once he had kidnapped Ollivander, however, he discovered the existence of the twin cores. He thought that explained everything. Yet the borrowed wand did no better against yours! So Voldemort, instead of asking himself what quality it was in you that had made your wand so strong, what gift you possessed that he did not, naturally set out to find the one wand that, they said, would beat any other. For him, the Elder Wand has become an obsession to rival his obsession with you. He believes that the Elder Wand removes his last weakness and makes him truly invincible. Poor Severus…”