Pyramids of Mars

LAURENCE: How could you possibly know that?

DOCTOR: Well, you see, Mister Scarman, I have the advantage of being slightly ahead of you. Sometimes behind you, but normally ahead of you.

LAURENCE: I see.

DOCTOR: I'm sure you don't, but it's very nice of you to try.

DOCTOR: The Earth isn't my home, Sarah. I'm a Time Lord.

SARAH JANE: I know you're a Time Lord.

DOCTOR: You don't understand the implications. I'm not a human being. I walk in eternity.

SARAH JANE: What's that supposed to mean?

DOCTOR: It means I've lived for something like seven hundred and fifty years.

SARAH JANE: Oh, you'll soon be middle aged.

“Evil? Your evil is my good. I am Sutekh the Destroyer. Where I tread, I leave nothing but dust and darkness... I find that good!”