It takes a great deal of bravery to stand up to our enemies, but just as much to stand up to our friends. ~Albus Dumbledore (Harry Potter and the Sorcerer's Stone)
You think the dead we loved ever truly leave us? You think that we don't recall them more clearly than ever in times of great trouble? Your father is alive in you, Harry, and shows himself plainly when you have need of him. ~Albus Dumbledore (Harry Potter and the Prisoner of Azkaban)
There are some things you can't share without ending up liking each other. ~Albus Dumbledore (Harry Potter and the Sorcerer's Stone)
And a bonus one, because it was so beautifully unexpected and perfectly placed...