Final answer:
Macbeth's motivation for murdering Macduff differs from his earlier murders as it is driven by fear, desperation, and vengeance, reflecting his descent into tyranny and paranoia.
Step-by-step explanation:
Macbeth's motivation for committing murders evolves over the course of the play. Initially, Macbeth murders King Duncan to fulfill the prophecy of becoming king and due to ambition, further spurred by Lady Macbeth's influence. This pivotal murder is driven by Macbeth's desire for power and his wife's questioning of his manhood. The murder of Banquo, his former friend and ally, is motivated by fear of the witches' prophecy that Banquo's descendants will inherit the throne, which threatens Macbeth's position. This murder is premeditated and executed with a calculated approach, showing Macbeth's increasing ruthlessness.
When it comes to Macduff's murder, Macbeth's motivation shifts significantly; it arises from a mixture of fear and desperation. Macbeth fears the potential threat Macduff poses after being warned by the witches to beware Macduff. Additionally, Macbeth seeks to secure his power by eliminating all threats, as his paranoia grows. Unlike the previous murders, there is also an element of vengeance, as Macbeth aims to punish Macduff for his disloyalty. This act indicates Macbeth's descent into tyrannical madness, committing murders with less rationale and more impulse, guided by paranoia and a desire to crush opposition.