Throughout Macbeth Shakespeare uses comparison and contrast to bring out characteristics of his main character, Macbeth. Shakespeare uses comparison with Duncan, Lady Macbeth, and Banquo to bring out aspects of Macbeth's character.
After hearing of Macbeth's courageousness on the battlefield, Duncan, a good and honest king, bestows the tittle of Cawdor on Macbeth. The king then proclaims his son Malcolm
to be Prince of Cumberland, in effect designating him
as successor to the throne of Scotland. This dramatic announcement of Duncan's chosen successor marks the beginning of an ironic story. It is at this point in the play that we, the audience, become fully aware of Macbeth's intentions to murder the king. Duncan hails Macbeth as his "worthiest cousin" and blindly entrusts his fate to one whom he considers his "peerless kinsman." Shakespeare concentrates on Macbeth's courage so that he can contrast it later on with the terror and panic of Macbeth's psychological anguish.
Lady Macbeth will stop at nothing -not even murder- to satisfy her driving ambition. She worries that Macbeth is "too full of the milk of human kindness" to go after the throne. She wants to be tough and begs the spirits to "unsex me here." Macbeth, on the other hand, hesitates to murder Duncan for several reasons. Among these reasons the earthly consequences frighten him the most. How would his new subjects react? Would the kingdom disrupt in chaos? Furthermore Macbeth cannot escape present punishment if he fails. We see Lady Macbeth's persuasiveness producing a new courage in her husband and that courage is manly enough to perform murder. Therefore, Macbeth has no reasons for murdering Duncan except for his "vaulting ambition," his lust for power. Throughout the play we see Lady Macbeth's and Macbeth's conscience, or lack of, change places. Macbeth transformed from having a guilt ridden conscience to having no...