Lady Macbeth sees herself as strong and ambitious in Act 1. She wants what she wants. When she gets Macbeth’s letter describing the witches’ prophecies, she latches on and does not let go. She wants to be queen, and she wants Macbeth to be king. She will stop at nothing, not even murder.
Lady Macbeth sees herself as someone who must take the reins in the relationship for what must be done...she is stronger than her husband who is "too full of the milk of human kindness" to fulfill such a deed as murder. She calls on the devils and spirits of darkness to "stop up the passage" to guilt and remorse...although we know they should have stopped them up a little more thoroughly since Lady Macbeth commits suicide based on her guilty conscience.
In Act I, Scene 5, Lady Macbeth perceives herself as strong, yet still womanly, imbued with those feminine traits which, stereotypically, make women the weaker sex. Even more than that, she asks the spirits to unsex her and to make her more like a man, a warrior, which is the quality that defines Macbeth at the onset of the play when he "unseam'd" Macdonwald "from the nave to th' chops" (1.2.23). Lady Macbeth is also typical in many ways, believing that she can persuade her husband on to the business of dispatching Duncan as she will "chastise with the valor of my tongue." Throughout literature, movies, and reality, we meet women who urge their husbands to commit deeds to elevate their positions; many television dramas are made up of this plot. Most recently, The Tudors, portrayed Anne Boleyn much as she was in reality, urging King Henry to commit foul acts to elevate her position. However, we discover shortly after that Lady Macbeth is not as strong as she appears; she tells us she could not murder Duncan herself as he too much resembled her father!
In this scene, Lady Macbeth calls on the powers of darkness to fill her with cruelty; she calls on the evil spirits to give her masculine qualities, to remove from her all that makes her soft and feminine so that she can be firm of purpose in order to convince her husband to commit murder. In this scene, she acts like a conjuring witch, reaching out to the forces of darknesss to aid her in this task.
She asks the night to cover their actions when they kill Duncan so that they can succeed. Lady Macbeth in this scene, is filled with unchecked ambition, cruelty and a desire for blood. She, at this point in the play, is the stronger, more cunning Macbeth. She will take charge of the planning; she will become the man.
"Under my battlements. Come, you spirits
That tend on mortal thoughts! unsex me here,
And fill me from the crown to the toe top full
Of direst cruelty; make thick my blood,
Stop up the access and passage to remorse,
That no compunctious visitings of nature
Shake my fell purpose, nor keep peace between
The effect and it! Come to my woman's breasts,
And take my milk for gall, you murdering
Wherever in your sightless substances
You wait on nature's mischief! Come, thick
night," And pall thee in the dunnest smoke of hell,
That my keen knife see not the wound it makes,
Nor heaven peep through the blanket of the
To cry 'Hold, hold!' (Act I, Scene V)
Lady Macbeth invokes the evil spirits in Act I, Sc. v, so that she can provoke Macbeth to kill Duncan. Lady Macbeth has already interpreted Macbeth’s nature which is “too full o’ th’ milk of human kindness”. She has understood that Macbeth cannot kill Duncan by himself. In this scene she asks the evil spirits to “fill” her “from the crown to the toe, top-full / Of direst cruelty”. This cruelty, she knows, will enable her to reawaken the evil nature of Macbeth and thereby help him to kill the king.