Macbeth begins with the three witches in a desolate place predicting the future. They are the characters that set the foundation for the play, indicating their pivotal role in directing the protagonists' actions as the story progresses. Moreover, they are also considered agents of evil because Shakespeare wrote Macbeth at a time where witches were known as the cause of illness, disaster, and death, which directly foreshadows the detrimental events to come.
The portrayal of the witches in Scene 3 draws directly on many of the beliefs about witchcraft that readers would have held. Their power over the elements means that they can control the winds, raise storms and sail in sieves. Shakespeare uses this to demonstrate the Witches’ vindictive nature, leaving the audience in no doubt as to their connection with the powers of evil.
Hearing the confirmation of the Witches' first prophecy, Macbeth cannot reconcile the fact of its truth with his intense and unnatural fear, or what he calls his "horrible imaginings." He admits to being so shaken by the news that his power to reason has been taken over by his imagination. This immediately shows his inferiority of power against the Witches, who have managed to manipulate his mind into murderous thoughts.
Banquo tries warning Macbeth of the consequences of the "instruments of darkness", which proves his character of being noble and honorable. Although he is susceptible to ambition like Macbeth, he does not bring corrupt thoughts to life. He is also, therefore, the wiser one when faced with temptation, unlike Macbeth who is too hooked on the idea of being King and turns a deaf ear to Banquo's doubts.
In preparation for the King's murder, Lady Macbeth wishes to be unsexed so that she can be cruel enough to persuade Macbeth and make him cruel too without feeling any remorse. Her willingness to bid the spirits in depriving her of her femininity, to thicken her blood, and to stop her ability to weep and then calling upon the night itself to hide her actions in a "blanket" of darkness portrays her potential influence and dominance over the male figure in her life.
Macbeth tries to tell her that he will proceed no further in this business, but she taunts him for his fears and attacks his manliness. Macbeth is astonished by her cruelty but eventually gives into her superiority for he respects her wishes. Lady Macbeth is seen to get what she wants by adding a distinction between masculinity and femininity using her own self-proclaimed manliness. She pours scorn upon her husband's lack of courage, expressing the power she has over his actions.