Twelfth Doctor: The silly old universe. The more I save it, the more it needs saving. It’s a treadmill. Yes, yes, I know. They’ll get it all wrong without me. I suppose one more lifetime wouldn’t kill anyone. Well, except me. You wait a moment, Doctor. Let’s get it right. I’ve got a few things to say to you. Basic stuff first. Never be cruel, never be cowardly… and never, ever eat pears! Remember… hate is always foolish… and love is always wise. Always try to be nice, but never fail to be kind. Oh, and you mustn’t tell anyone your name. No-one would understand it, anyway. Except… Except children. Children can hear it… sometimes… if their hearts are in the right place, and the stars are, too. Children can hear your name. But nobody else. Nobody else, ever. Laugh hard… run fast… be kind. Doctor… I let you go.
From Doctor Who – Season 11 Episode 0: ‘Twice Upon a Time’ (11×00 / Christmas special 2017)