Poetic justice is portrayed in the death of Macbeth himself. He who had caused the death of so many to gain the throne loses his life because he has gained that throne. In Act V Scene 8 Lines 32-40: "I will not yield/ To kiss the ground before young Malcolm ...
Poetic justice is portrayed in the death of Macbeth himself. He who had caused the death of so many to gain the throne loses his life because he has gained that throne. In Act V Scene 8 Lines 32-40: "I will not yield/ To kiss the ground before young Malcolm's feet / And to be baited with the rabble's curse. / Though Birnham Wood be come to Dunsinane / And though opposed, being of no woman born, / Yet I will try the last. Before the body / I throw my warlkike shield. Lay on, Macduff, / And damned be him that first cries 'Hold! Enough!'"
Macbeth first acted on the words of the witches, but did not give their second prophecy enough heed, and thus did not take the necessary steps that could have saved his throne, as he took them to procure it. What got him the throne caused himto lose the throne, and his life. His pride, as well as his insight, failed him.
As for destiny vs. free will, the witches' prophecy is the most notable example. (Act 1 Scene 3 Lines 51-53). It is Macbeth's destiny to be king, but there is not mention as to how, through his free will, he is to bring this about. Destiny implies that what will happen will happen, regardless of one's actions. Free will, however, necessitates action. While Macbeth accepts his destiny, it is his choice of how to exert his free will that leads to his downfall.
Macbeth is accused of weakness (having too much "the milk of human kindness) that will ruin their chances of successfully eliminating Duncan. Though she wishes the deed done, she does not suggest that she perform it rather than her husband. This is a reference to the gender roles of the time, in which the wife is submissive to the leadership of her husband. Lady Macbeth strains at this, crying out "unsex me here" in Act i Scene 5 Line 48. It's not that she wishes to be a man, but that the matter of gender should not be an issue, which it in fact is.
As far as "nature out of order,' an example would be the environmental conditions that reflect the murder of Duncan on the night of his death (Act II Scene 3 Lines 61-69). Rather than man responding to nature and its conditions, the order is reversed, when the world trembles at the death of an innocent man (parallel accounts on earthquakes and darkness at the crucifixion of Christ). The personification of nature provides a witness to Macbeth's evil.