Why is MacDuff an effective foil for MacBeth in Macbeth?
A foil is a character who exists to provide contrast. Macbeth and Macduff are opposites. Although both are brave soldiers and noblemen when the story starts, Macbeth becomes a murderer and a tyrant and Macduff vows to stop him.
Macbeth is the Thane of Glamis and Macduff is the Thane of Fife. Both are important nobles to the kingdom, and both are apparently loyal to Duncan.
Macduff is everything Macbeth is not. He is sensitive and emotional. When King Duncan is murdered, he is horrified while Macbeth—Duncan’s murderer—only pretends to be.
O horror, horror, horror! Tongue nor heart
Cannot conceive nor name thee. (Act 3, Scene 3, p. 34)
He also asks people to look after Lady Macbeth when she seems to faint. He is concerned with her health and safety even as the king is dead. This is completely contrary to Macbeth, who thinks only of himself.
Macduff seems aware that Macbeth is up to something. He becomes suspicious. Banquo says he suspects something.
Against the undivulged pretence I fight
Of treasonous malice (Act 2, Scene 4, p. 37)
Macduff replies: “And so do I.”
Clearly, he suspects foul play. It is not much of a step from there to suspecting Macbeth, in whose castle Duncan was killed.
From there, tragedy strikes. When Macbeth reaches out and has Macduff’s wife, son, and entire household killed, the two are fated to struggle to the death. Macduff cannot let such an insult stand.
Malcolm, who has been feeling Macduff out to see if he really is loyal, tells Macduff to “dispute it like a man” and he says he will, but he still feels it.
But I must also feel it as a man.
I cannot but remember such things were,
That were most precious to me. (Act 3, Scene 3, p. 74)
Of course, Macduff is not the treacherous one. He is determined to kill Macbeth in order to return justice and peace to the land. He cares as much about his country as getting his revenge.
In the end, one foil often ends up killing the other. Macduff kills Macbeth, the violent version of himself, because he has gone to the dark side. He has turned evil. Macduff feels responsible for taking him out.
Behold where stands
The usurper's cursed head. The time is free.
I see thee compass'd with thy kingdom's pearl (Act 5, Scene 8, p. 90)
A foil is a character that exhibits contrasting qualities with another character in order to emphasize the other character's traits. Macduff is an effective foil to Macbeth because he exhibits opposite character traits, which contrast greatly with Macbeth's personality and actions throughout the play. Macbeth is portrayed as a treacherous, ambitious individual with no loyalty and an authoritative disposition. He is also depicted as a bloodthirsty tyrant, who is callous in nature and overconfident that he will defeat his enemies. In contrast, Macduff is depicted as a loyal, honest person, who fits the archetype of an avenging hero throughout the play.
In act 4, scene 3, Macduff begs Malcolm to return to Scotland and vows to support him in his fight against Macbeth. However, Malcolm lies to Macduff by telling him that he is an utterly despicable human being, who is not fit to be king. Macduff is deeply saddened by Malcolm's news and cries for his country. This scene depicts Macduff as a compassionate, genuine person, who is more concerned about the well-being of his country than he is about his own life. Macduff then risks his life for his country by leading the troops against Macbeth and defeating the tyrant in battle.