Glamis hath murdered sleep, and therefore Cawdor
     Shall sleep no more, Macbeth shall sleep no more.

There comes a sound of knocking.  It should be perfectly familiar to him; but he knows not whence, or from what world, it comes.  He looks down at his hands, and starts violently:  ‘What hands are here?’ For they seem alive, they move, they mean to pluck out his eyes.  He looks at one of them again; it does not move; but the blood upon it is enough to dye the whole ocean red.  What has all this to do with fear of ‘consequences’?  It is his soul speaking in the only shape in which it can speak freely, that of imagination.

So long as Macbeth’s imagination is active, we watch him fascinated; we feel suspense, horror, awe; in which are latent, also, admiration and sympathy.  But so soon as it is quiescent these feelings vanish.  He is no longer ‘infirm of purpose’:  he becomes domineering, even brutal, or he becomes a cool pitiless hypocrite.  He is generally said to be a very bad actor, but this is not wholly true.  Whenever his imagination stirs, he acts badly.  It so possesses him, and is so much stronger than his reason, that his face betrays him, and his voice utters the most improbable untruths[218] or the most artificial rhetoric[219] But when it is asleep he is firm, self-controlled and practical, as in the conversation where he skilfully elicits from Banquo that information about his movements which is required for the successful arrangement of his murder.[220] Here he is hateful; and so he is in the conversation with the murderers, who are not professional cut-throats but old soldiers, and whom, without a vestige of remorse, he beguiles with calumnies against Banquo and with such appeals as his wife had used to him.[221] On the other hand, we feel much pity as well as anxiety in the scene (I. vii.) where she overcomes his opposition to the murder; and we feel it (though his imagination is not specially active) because this scene shows us how little he understands himself.  This is his great misfortune here.  Not that he fails to realise in reflection the baseness of the deed (the soliloquy with which the scene opens shows that he does not).  But he has never, to put it pedantically, accepted as the principle of his conduct the morality which takes shape in his imaginative fears.  Had he done so, and said plainly to his wife, ’The thing is vile, and, however much I have sworn to do it, I will not,’ she would have been helpless; for all her arguments proceed on the assumption that there is for them no such point of view.  Macbeth does approach this position once, when, resenting the accusation of cowardice, he answers,

     I dare do all that may become a man;
     Who dares do more is none.

She feels in an instant that everything is at stake, and, ignoring the point, overwhelms him with indignant and contemptuous personal reproach.  But he yields to it because he is himself half-ashamed of that answer of his, and because, for want of habit, the simple idea which it expresses has no hold on him comparable to the force it acquires when it becomes incarnate in visionary fears and warnings.