This quote is a metaphor for the characters as although they may seem completely normal; but underneath they are filled with sins and weakness.
In Macbeth there are many human weaknesses featured, for example: lust, greed and doubt.
Lady Macbeth is shown as a very cruel character with many weaknesses that all lead to her wanting her husband to be King which shows an incredible lust for power. ‘Glamis thou art, and Cawdor, and shalt be what thou art promis'd. Yet do I fear thy nature, it is too full o' th' milk of human kindness to catch the nearest way.’ This shows that she is finding a fault in her husband for being too kind to commit treason and kill the king. It shows that she will go to incredible measures to become queen and murder isn’t going to stop her.
Another one of Lady Macbeth’s weaknesses is her need to manipulate Macbeth. "Hie thee hither, That I may pour my spirits in thine ear and chastise thee with the valour of my tongue..." This shows us that she feels in order to convince Macbeth to do this treacherous deed she is going to have to pour her ideas into his mind. Furthermore, she uses the word ‘chastise’ which can be seen as though she is punishing Macbeth for not wanting to kill King Duncan.
Lastly Lady Macbeth is shown as a heartless character. “Have pluck'd my nipple from his boneless gums, And dash'd the brains out, had I so sworn as you have done to this” This shows us that she is so callous that even a baby of her own womb does not mean anything to her and she would rather it dead. This, also, ruins Macbeth’s plans to have an heir to the throne as he is unable to trust such a sick and twisted woman with his baby.
Macbeth is a prime example of a man filled with pride, ambition and confidence. You can see this right from the start of the play. As soon as Macbeth is named Thane of Cawdor, fulfilling one of the witches visions, he begins to contemplate how to become king as the