Fair is foul, and foul is fair
_
Act I, Scene I

For a charm of powerful trouble,
Like a hell-broth boil and bubble.

Double, double toil and trouble;
Fire burn, and caldron bubble!
_
Act IV, Scene I

And damn'd be him that first cries, 'Hold, enough!'
_
Act 5, Scene 8

William Shakespeare, The Tragedy of Macbeth,