Malcolm tests Macduff’s loyalty in Act 4, Scene 3, and Macduff passes the test and proves he is a loyal supporter.
When Macbeth kills Duncan, Malcolm flees to England. He knows he will be suspected if he stays, and instead he can use England as a staging area to develop an army of supporters still loyal to him. Macduff follows, suspecting that Macbeth might have killed Duncan.
Malcolm is suspicious of everyone. He feels like he can trust Macduff, but he needs to make sure.
Be not offended;
I speak not as in absolute fear of you.
I think our country sinks beneath the yoke;(45)
It weeps, it bleeds, and each new day a gash
Is added to her wounds. (Act 4, Scene 3)
Malcolm gives Macduff all of the reasons why he would not be a good king, including his age and inexperience. He would be lustful and violent, and generally untrustworthy. Macduff does not take the bait. He stays staunch and true, weeping over Scotland’s fate with the bloody tyrant Macbeth. Malcolm relents.
Macduff, this noble passion,
Child of integrity, hath from my soul(130)
Wiped the black scruples, reconciled my thoughts
To thy good truth and honor. (Act 4, Scene 3)
In the end, Malcolm realizes that he will make an excellent king. He is intelligent and honest, and his love of country speaks for itself. While his brother Donalbain flees and does not bother to help, Malcolm puts all of his efforts into returning his family to the throne and freeing the kingdom from Macbeth’s cruelty and ambition.
This scene marks a turning-point in the Macbeth-centered script. We see that Macbeth is doomed, because there is someone else ready to take him out. Macduff and Malcolm have both been wronged, but they are not revenge-focused. Each of them is more interested in returning the beloved homeland to a noble and honest king.