Harry Potter and the Half-Blood Prince
Professor Trelawney, the often tipsy Divination teacher who is furious that she must share her course load this year with the centaur Firenze, is credited with providing the famous prophecy the year before Harry was born that marked him as the Chosen One. The prophecy is revealed to us in Chapter 37 of Book 5, Harry Potter and the Order of the Phoenix, as the following:
"The one with the power to vanquish the Dark Lord approaches ... Born to those who have thrice defied him, born as the seventh month dies ... And the Dark Lord will mark him as his equal, but he will have power the Dark Lord knows not ... And either must die at the hand of the other for neither can live while the other survives ... The one with the power to vanquish the Dark Lord will be born as the seventh month dies..."
Professor Trelawney hoards her sherry in the oddest of places, including the Room of Requirement. Pay attention to the cards that she holds throughout the story – could they mean anything?