LADY              Who was it that thus cried? Why, worthy thane,

You do unbend your noble strength to think

So brain-sickly of things. Go, get some water

And wash this filthy witness from your hand.

Why did you bring these daggers from the place?

They must lie there. Go, carry them, and smear

The sleepy grooms with blood.

MACBETH                              I’ll go no more.

I am afraid to think what I have done.

Look on’t again I dare not.                (2.2.41-49)

So Lady Macbeth has to take charge, because Macbeth is really losing it (or that’s easier to believe, perhaps, than the terrible things he’s reporting, the voice telling him ‘sleep no more’): who was it that thus cried? She could sound scornful, or reassuring, a parent to a child. Who could it have been, really? You’re just hearing things, you big silly. But there’s a bit of bite to her response, which is more rebuke than reassurance: worthy thane (reminding him of his status, his rank) you do unbend your noble strength to think so brain-sickly of things. To unbend is to slacken, as one would a bowstring; it’s an image of weakness and impotence, a lack of the purpose and readiness which noble strength should entail. Pull yourself together! Get a grip! (Tightness, tautness, rigidity; it’s a return to the undercurrent of phallic mockery that marked their previous interaction.) Be a man! Stop being so weak and wobbly—and stop indulging this brainsickness, these delusions of voices, this compulsion to repeat, this madness. And as one would say to a child, very deliberately: what you need to do now is get some water and wash this filthy witness from your hand. The blood as witness, not simply as evidence or sign or trace is partly there for metrical reasons but it also perhaps invokes Cain, once again, the Bible’s first murderer: God asks the guilty Cain ‘What hast thou done? the voice of thy brother’s blood crieth unto me from the ground’ (Genesis 4.10). Blood, in this play, readily becomes animate, and has a kind of agency.

Then Lady Macbeth spots the really crucial thing, and that she hasn’t noticed before is perhaps a sign of her own precarious state, or perhaps she can’t believe that he’s been so stupid. And it’s dark. Why did you bring these daggers from the place? they must lie there. You fool! (But also: the place, not the body; not even the chamber. Can’t quite bear to bring it into focus.) You’ve got to take them back, it’s crucial: carry them, and smear the sleepy grooms with blood. Really frame the servants; smear them, as they sleep, drugged, with the blood of their murdered master. (The sense of smearing as discrediting is current.) Macbeth’s had enough though, and he’s about to snap: I can’t do it, I can’t go back in there; I’ll go no more. I am afraid to think what I have done, let alone to see it; look on’t again I dare not. (The emphasis falls on think; I can’t bear to contemplate what I’ve done, what I’ve become, I can’t get it out of my head.) The thought of seeing it again is beyond imagination.