In Act IV, scene ii of Macbeth, Duncan is dead, and Macbeth has been making sure that all who may stand in his way are eliminated. From what the witches tell him, he is not the only one destined to be king, and so he has been setting about removing any threat to his position. Macduff may or may not be a threat, but Macbeth must make "double sure".
Scene ii begins with Lady Macduff expressing her doubts over her husband's "madness" in leaving his family in the face of danger. The scene allows the audience to process all that has happened before. The audience needs to feel the pain of those affected and not just witness Macbeth's killing spree. The audience is able to appreciate Lady Macduff's feelings and grasp the very real physical danger. Any member of the audience now has an opportunity to reflect on what he or she may have done or should have done in similar circumstances. Lady Macduff also points out that no one is safe in "this earthly world" (line 73). The protection of women who "have done no harm" and their children is not guaranteed. This would intensify the audience's anguish as events unfold.
This scene therefore ensures the audience's very personal involvement. The audience may expect Macduff's son to escape, as Fleance escaped. However, by the end of the scene, with the boy dead, the audience is suitably entangled in the drama and is assured that there is much more to follow.
The conversation between Lady Macduff and her son in act 4 sc.2 shows a loving mother talking to her child thus highlighting love, care and concern that constitute motherhood. Lady Macduff is a wife and a mother and, unlike the other Lady in the play, Lady Macbeth, she is not bothered about the politics of power. She is upset at her husband's flight to England and apprehends trouble. She is very much concerned about her children and herself being unprotected because of her husband's flight. Thus she stands as a foil to the other Lady who even wanted to kill her baby while giving it a breast-feed.
Macduff's son is very innocently witty and speaks in his boyish playfulness. Nevertheless the boy betrays adult-like wisdom laced with his gift of humor and mischief , e.g.
Lady Macduff: But how wilt thou do for a father?
Son: If he were dead, you'd weep for him: if you would not, it were a good sign that I should quickly have a new father.
He even underpins the moral inversion of the Macbeth-world:
Son: Then the liars and swearers are fools, for there are liars and swearers enow to beat the honest men and hang up them.
This mother-child conversation shows the goodness of love in a suffocating world of ambition, violence and tyranny. When the murderers enter soon thereafter and kills the boy before our eyes, we can guess that the bottom line of Macbeth's degeneration is reached. This conversation underscores the only alternative discourse in a world of mad rush for power, namely, the discourse of love , love that ambition seems to throttle.