Sam Spade: You don't have to trust me as long as you can persuade me to trust you.

Sam Spade: You killed Miles and you're going over for it.

Sam Spade: You're good, you're very good.

Kasper Gutman: You're a close-mouthed man?
Sam Spade: Nah, I like to talk.
Kasper Gutman: Better and better. I distrust a close-mouthed man. He generally picks the wrong time to talk and says the wrong things. Talking's something you can't do judiciously, unless you keep in practice. Now, sir. We'll talk, if you like. I'll tell you right out, I am a man who likes talking to a man who likes to talk.
Sam Spade: Swell. Will we talk about the black bird?

Brigid O'Shaughnessy: I haven't lived a good life. I've been bad, worse than you could know.
Sam Spade: You know, that's good, because if you actually were as innocent as you pretend to be, we'd never get anywhere.

Bryan: Who killed Thursby?
Sam Spade: I don't know.
Bryan: Perhaps you don't, but you could make an excellent guess.
Sam Spade: My guess might be excellent or it might be crummy, but Mrs. Spade didn't raise any children dippy enough to make guesses in front of a district attorney, and an assistant district attorney and a stenographer.
Bryan: Why shouldn't you, if you have nothing to conceal?
Sam Spade: Everybody has something to conceal.