With his brother Donalbain, Malcolm quickly ascertains the danger of remaining in Scotland and flees the country (Act II, Scene 3). By the time he reappears, in Act IV, Scene 3, he has won the support of Edward the Confessor (King of England), he has mobilized troops under Northumberland and Siward, and (to borrow a phrase from King Lear) he is “every inch a king.”
If Macduff is the stereotypical revenge, Malcolm is the embodiment of all that is good in kingship, and this is seen particularly in Act IV, Scene 3, in which he tests the allegiance of Macduff. His testing of Macduff, although dramatically longwinded, is psychologically accurate. By pretending to be what he is not, he hopes to coax from Macduff a confession of his loyalty. This feature of his character — playing a part in order to strengthen the prospect of good — is in stark contrast to Macbeth, who plays a part in order to advance his own evil. In the final scene of the play, Malcolm is presented as the future king. His use of the phrase “by the grace of Grace” indicates the importance that he attaches to the service of good and reminds the audience of his direct descent from one who ruled by divine right, as opposed to Macbeth, who usurped the throne. Like his father Duncan, Malcolm is the representative of order.