How we cite our quotes: All quotations are from Harry Potter and the Half-Blood Prince.
Quote #4
DUMBLEDORE: Thievery is not tolerated at Hogwarts, Tom. At Hogwarts, you'll be taught not only how to use magic, but how to control it.
Well, looks like Voldemort was dishonest from the start—like, even when he was a young, innocent-looking kid. When Dumbledore went to visit him at the orphanage, he detected a stolen item in Tom's closet. Dumbledore seemed to want to give Tom a fresh start at Hogwarts, but as we all know, that…didn't exactly work out.
Quote #5
SLUGHORN: I beg your pardon? I don't know anything about such things and if I did, I wouldn't tell you. Now, get out of here at once, and don't let me ever catch you mentioning it again!
This moment occurs in a memory of Slughorn's—a memory that's been altered. In this version of Slughorn's history, he is totally refusing to talk to Voldemort about some dark magicky stuff that the young Dark Lord came across in the restricted section of the library. We're guessing the true version of the memory is a lot different, because otherwise, why would Slughorn have doctored it?
Quote #6
DUMBLEDORE: Confused? I'd be surprised if you weren't.
HARRY: Well, I don't understand. What happened?
DUMBLEDORE: This is perhaps the most important memory I've collected. It is also a lie. This memory has been tampered with by the same person whose memory it is. Our old friend, Professor Slughorn.
HARRY: But why would he tamper with his own memory?
DUMBLEDORE: I suspect he's ashamed of it.
HARRY: Why?
DUMBLEDORE: Why, indeed? I asked you to get to know Professor Slughorn and you have done so. Now I want you to persuade him to divulge his true memory. Any way you can.
HARRY: I don't know him that well, sir.
DUMBLEDORE: This memory is everything. Without it, we are blind. Without it, we leave the fate of our world to chance. You have no choice. You must not fail.
Gulp. Harry and Dumbledore have just viewed Slughorn's tampered-with memory, and now Harry has been tasked with getting the real story from Slughorn. "Any way you can." Sounds like maybe Harry could end up getting involved in some deception himself.