Malcolm is King Duncan’s eldest son, brother of Donalbain, and heir to the throne, which is why he is called Prince of Cumberland. In the final scene of Macbeth, Malcolm is to be crowned as the new king. This means that Shakespeare needs to demonstrate to us throughout the play that Malcolm is in fact a worthy ruler.
Contrary to his gullible father, Malcolm is suspicious and realises that he is in danger after Duncan’s murder. He decides to flee to England to persuade the English king to support him in overthrowing Macbeth (Act 2, Scene 3).
When Macduff flees too and comes to see him, Malcolm is again very cautious and first treats Macduff as Macbeth’s spy. Malcolm tests Macduff’s loyalty by lying and saying that he is full of negative qualities which would make him an even worse king than the tyrant Macbeth (Act 4, Scene 3). All of this shows us that M...