Macbeth (ii) — Out, damned spot

LADY MACBETH
    Yet here's a spot.
DOCTOR
    Hark! She speaks. I will set down what comes from her, to satisfy my remembrance the more strongly.
LADY MACBETH
    Out, damned spot! Out, I say!—One, two.
    Why, then, 'tis time to do 't. Hell is murky!—Fie, my lord, fie!
    A soldier, and afeard? What need we fear who knows it,
    when none can call our power to account?—Yet
    who would have thought the old man to have had so much blood in him.

—Shakespeare, Macbeth

(Act 5, Scene 1)