LitCharts assigns a color and icon to each theme in Macbeth, which you can use to track the themes throughout the work.
Ambition
Fate
Violence
Nature and the Unnatural
Manhood
Summary
Analysis
In a cavern, the weird sisters throw awful ingredients such as "eye of newt and toe of frog" (4.1.14) into a cauldron full of a boiling brew. Hecate arrives, and all dance and sing. One witch cries out "Something wicked this way comes" (4.1.62): Macbeth enters. He commands the witches to answer his questions.
There is a resemblance between Macbeth and the witches now. All are wicked, all are unnatural.
Finally, a child wearing a crown and holding a tree appears. It says that Macbeth will not be defeated until Great Birnam Wood marches to Dunsinane Hill. Macbeth is pleased: since forests don't march, he must be invincible!
Macbeth wants to know one more thing: will Banquo's heirs have the throne? The witches perform a final conjuring. Eight kings appear walking in a line, the eighth holding a mirror, and all of them followed by Banquo's ghost. Macbeth, furious at this sign that Banquo's heirs will get the throne, demands answers. But Hecate mocks him and the witches vanish.
The king holding the mirror symbolizes King James who ruled England when Shakespeare wrote Macbeth, and whose family traced its ancestry back to Banquo.
Lennox enters. He brings word that Macduff has fled to England. In an aside, Macbeth scolds himself for failing to kill Macduff when he wanted to earlier. He vows in the future to act on every impulse, and decides to attack Macduff's castle and kill anyone connected to him: servants, wife, and children.
Ambition and fear have pushed Macbeth that final step: he is no longer targeting just his political enemies, but also their innocent families. Macbeth is now truly a monster.