There can be no argument that Shakespeare was a masterful storyteller and dramatist, describing characters and their lives with brilliant clarity with his words. In Macbeth, all of the characters that impact the reader (or audience) are fleshed out with full-bodied imagery. Macduff is no exception. It is not until after the Macbeths have killed Duncan that Macduff appears on stage, becoming Macbeth's nemesis.
Imagery is a device that when used—by providing minute and precise details—creates a mental image of what is being described, in the reader's mind. Imagery is...
...the forming of mental images, figures, or likenesses of things. It is also the use of language to represent actions, persons, objects, and ideas descriptively.
In Act Four, scene two, Lady Macduff is deeply concerned that her husband has chosen such an unstable time (under the rule of a dangerous king, Macbeth) to leave Scotland for England. She accuses her husband of being crazy to do so, making it look as if he is a traitor, inferring that he has put his family's safety at risk. The imagery here makes note of what makes one guilty of treason—one's actions or one's fears:
...when our actions do not,
Our fears do make us traitors. (3-4)
She goes on to criticize his instincts as a parent, comparing him to a wren—a simple bird that has more courage than he does:
...for the poor wren,
The most diminutive of birds, will fight,
Her young ones in her nest, against the owl. (9-11)
Later in the same scene, when the murderers come looking to kill Macduff, Lady Macbeth infers that the murderer is unholy, and her husband is all the things Ross had said (noble, wise, etc.).
Where is your husband?
I hope, in no place so unsanctified
Where such as thou mayst find him. (76-78)
In scene three, Macduff goes to England to enlist Malcolm (who has fled there for his safety) to return to fight for Scotland. Malcolm distrusts Macduff, fearful that he might be secretly working for Macbeth, intent upon harming the true heir of Scotland's throne. He notes that Macduff could potentially sacrifice Malcolm to please Macbeth (Macduff's king), comparing this situation to ritualistic sacrifice practiced in many ancient cultures:
I am young, but something
You may deserve of him through me; and wisdom
To offer up a weak, poor, innocent lamb,
T'appease an angry god. (14-17)
Malcolm goes on to use an allusion with regard to Macduff's potential deceit simply to follow the orders of his king:
Angels are bright still, though the brightest fell... (22)
This is a Biblical allusion to Lucifer turning on God and being cast out of heaven.
Malcolm tests Macduff to see if he can be trusted. Once assured, he describes Macduff as:
Child of integrity... (115)
This means that Macduff is ethical and moral, parented by goodness. In this example, personification is used in portraying integrity as a human being: a parent.
Malcolm's speech to Macduff when he learns of the slaughter of his children provides imagery of Macduff deep love for his family; Malcolm comments on Macduff's pain, but tells him not only to be a man, but to use the anger to feed his need for revenge. Macduff is described as a caring family man, but also a just man.
His sense of justice is carried out as he kills Macbeth, leaving the way clear for Malcolm to become King of Scotland.