SARAH JANE: Doctor, you're being childish.

DOCTOR: Well of course I am. There's no point in being grown up if you can't be childish sometimes.

“Courage isn’t just a matter of not being frightened, you know. It’s being afraid and doing what you have to do anyway.”

“When people need help, I never refuse.”

“None of us know for sure what's out there. That's why we keep looking. Keep your faith. Travel hopefully. The universe'll surprise you... constantly.”