Harry Potter and the Order of the Phoenix
"She says that on no account whatsoever are you to take part in an illegal secret Defense Against the Dark Arts group. She says you'll be expelled for sure and your future will be ruined. She says there will be plenty of time to learn how to defend yourself later and that you are too young to be worrying about that right now. She also" (Sirius's eyes turned to the other two) "advises Harry and Hermione not to proceed with the group, though she accepts that she has no authority over either of them and simply begs them to remember that she has their best interests at heart." (17.219)
Without preamble, Harry told his godfather every detail of the vision he had had, including the fact that he himself had been the snake who had attacked Mr. Weasley.
When he paused for breath, Sirius said, "Did you tell Dumbledore this?"
"Yes," said Harry impatiently, "but he didn't tell me what it meant. Well, he doesn't tell me anything any more."
"I'm sure he would have told you if it was anything to worry about," said Sirius steadily. (22.136-139)
"Well, for a first attempt that was not as poor as it might have been," said Snape, raising his wand once more. "You managed to stop me eventually, though you wasted time and energy shouting. You must remain focused. Repel me with your brain and you will not need to resort to your wand."
"I'm trying," said Harry angrily, "but you're not telling me how!"
“Manners, Potter," said Snape dangerously. (24.198-200)