The last appearance of Lady Macbeth before she sleepwalks onto the stage, in Act V, scene i, is the banquet scene and its aftermath, Act III, scene iv. Lady Macbeth does accept the guilt for her part in the murder up to this point, in fact she revels in the murder and all the guilt that can be accepted. In Act II, scene ii, when Macbeth won't return the daggers to the crime scene, she does so herself. Upon her return, she says this to Macbeth:
My hands are of your colour; but I shame
To wear a heart so white.
She is implying that any remorse or angst he feels over the murder is the sign of a coward. Lady Macbeth bears her part in the murder, her guilt, as a badge of honor in the first Acts of the play. It is her 180 degree turn in Act V that reveals the dark side of the effect of the murder and its guilt on her sanity.
But, even though Lady Macbeth proudly bears her part in the murder, her guilt, Shakespeare does provide some ironic foreshadowing of what is to come in Act V for Lady Macbeth. At the very end of Act III, scene iv, as she attempts to sooth the rattled Macbeth, she says:
You lack the season of all natures, sleep.
and Macbeth answers:
Come, we'll to sleep. My strange and self-abuse
Is the initiate fear that wants hard use;
We are yet but young in deed.
The mention by Lady Macbeth of sleep as the restorative for Macbeth's addled mind, is ironic because it will be her lack of sleep and her restless sleepwalking that reveal how her guilt has robbed her of her peace of mind.
And, interestingly, it is Macbeth who realizes that he must shake off his regret and remorse in order to be in it for the long haul. Throughout the remainder of the play, he is the one who freely accepts his own guilt while continuing to murder and commit evil with a free conscience. It is, ultimately, Lady Macbeth, who is consumed and taken down by her own feelings of remorse and regret.
For more analysis of Lady Macbeth and guilt, please follow the links below.