Act 4, Scene 2: Lady Macduff asks Ross why her husband has suddenly fled to England. She is not aware of the troubles between Macbeth and Macduff and does not realize that she is in danger. Lady Macduff decides that her husband left his family because he did not love them anymore. Ross tries to comfort her and warns her that Scotland is a dangerous place to be at the present.
Lady Macduff tells her young son that Macduff is dead to ease the pain of his departure from the family. She also tells him that his father was a traitor. A messenger runs in and interrupts the mother-son conversation, telling Lady Macduff to escape while she can. A few moments later, murderers under the bidding of Macbeth enter the castle and kill Lady Macduff and her son.
Act 4, Scene 3: Macduff has found Malcolm in England and the two are conversing in front of the king's palace. The two lament the evils that Scotland has suffered under the "tyrant" Macbeth's reign. Macduff tries to convince Malcolm to overthrow Macbeth. Malcolm, however, is still wary of anyone from Scotland. Thus, he pretends to be inferior to Macbeth and refuses to take the throne. He falsely states that he is licentious, greedy and materialistic. Macduff consoles Malcolm and tells him that anyone would be better on the throne than Macbeth. Touched by his patriotism and true compassion, Malcolm realizes that Macduff is not a spy and apologizes for lying to him. He agrees to help Macduff and Siward fight Macbeth.
After the two swear to help each other, Malcolm tells Macduff about the virtues of the English king. Supposedly, he is able to heal people suffering from scrofula (a tuberculosis of the lymphatic glands) by merely touching them. On a historical note, it is believed that Shakespeare's English king was based after King Edward. Edward was a saintly monarch who had the gift of healing his subjects from scrofula. Malcolm's praises of this king provides a direct contrast to the sinister Macbeth, who kills his subjects instead of healing them.
Ross enters the scene at this time, bearing bad news from Scotland. He tells Macduff that his family has been murdered and that the Scottish people are praying for a deliverer. Enraged and wrought with grief, Macduff resolves to get his revenge by killing Macbeth. Ross, Macduff, Malcolm, Siward and ten thousand men immediately leave England to war with Macbeth.