Betrayal, the corrupting force of unchecked ambition, the contrast between kingship and tyranny, and the relationship between masculinity and cruelty are topics worth discussing. All these themes are prominent in the Scottish play.
Betrayal and Murder
The obvious theme of Macbeth is betrayal. Betrayal, however, goes beyond Macbeth's gruesome murder of the the king.
Betrayal in Macbeth includes
(1) Macbeth and Lady Macbeth's disregard for the laws of hospitality (murdering your guest automatically diqualifies you from host of the year nominations in Shakespeare's time)
(2) Macbeth's breaking of the king-subject covenant to which he is bound
(3) Macbeth betrays Banquo, to whom he is connected by battle and by knowledge of the witches' prognostications
(4) Macbeth betrays Scotland by killing a worthy king and usurping the throne
(5) Macbeth betrays his own nature through the butchery of Macduff's family; (5) Macbeth betrays Duncan by killing one who has shown kindness toward him and granted him titles and riches.
Macbeth is not the only one guilty of betrayal in Macbeth. Lady Macbeth, in addition to her betrayal of hospitality, betrays the feminine nature to spur her and her husband to commit murder. She also betrays herself as she sleepwalks in act V. The play begins with the betrayal of Scotland by Norway and the thane of Cawdor. Macduff also betrays his own family by fleeing Scotland and leaving his family vulnerable to attack.
More Macbeth Themes
The corrupting force of unchecked ambitiontakes control of Macbeth as demonstrated by his murderous progression: (1) The kernel of ambition is placed in Macbeth by the Weird Sisters in Act I; (2) Macbeth hesitates killing the king, only does so with his wife's urging, and immediately regrets his treachery; (3) He fears Banquo and Fleance and orders their murder; (3) He orders the ruthless murder of Macduff's family to assert his power. Macbeth eventually usurps his wife's role as supreme possessor of cruel ambition by play's end.
The contrast between kingship and tyranny is brought forth with a comparison of King Duncan and King Macbeth. Duncan's benevolence and merit-based rewards, such as making Macbeth thane of Cawdor, earn him the honor of king. Macbeth's treachery, including the murders of Duncan, Banquo, and Macduff's family, earns him the title of tyrant.
The inherent cruelty in masculinity is ironically represented best by Lady Macbeth who throws off her feminine nature in order to embrace the cruelty of murdering the king. Lady Macbeth criticizes her husband for his lack of masculinity several times throughout the play.
She tells him to "man up" and go through with Duncan's murder. She scolds Macbeth for his womanly reaction in not wanting to return the bloody daggers, and tells him once again to be a man after Macbeth sees Banquo's ghost at dinner.
The contrast between perception and reality is evident from the play's initial scene with the witches' utterance "fair is foul and foul is fair." This contrast occurs throughout as Duncan has a false sense of security while staying at Inverness, the false sense of security Lady Macbeth gives Banquo before Banquo's murder, and the false sense of security the Weird sisters give to Macbeth.
The misperception that Donelbain and Malcolm are guilty of their father's murder on account of their fleeing to England and the misperception that Fleance is guilty of Banquo's murder on account of his fleeing adds to this Macbeth theme.