What is the significance of the second apparition, "a bloody child"?
In Act Four, Scene 1, Macbeth visits the Three Witches to learn more about his initial prophecy. The Three Witches conjure several apparitions that give Macbeth enigmatic messages about his future. After witnessing the first apparition where a head wearing an armored helmet tells Macbeth to beware of Macduff, an apparition of a bloody child appears. The bloody child tells Macbeth to be violent, bold, and resolute. It then tells Macbeth to laugh and scorn the power of man because nobody born from a woman will ever harm him. This second apparition is significant because it gives Macbeth a false sense of security and encourages his tyrannical behavior. Macbeth is comforted and feels confident in his ability to maintain his position as king. Following his second encounter with the witches, Macbeth vows to act immediately on his impulses. The first thing Macbeth does is send assassins to Macduff's home to slaughter his wife and children. In this way, the apparition of the bloody child foreshadows the death of Macduff's children. At the end of the play, Macbeth courageously encounters Macduff because he believes that Macduff is incapable of harming him. However, Macbeth learns that Macduff was "untimely ripp'd" from his mother's womb during a Caesarean section, which gives him the ability to harm Macbeth according to the witches' prophecy.
The bloody child tells Macbeth, "No man born of woman shall harm Macbeth." This prophecy comforts Macbeth despite the first apparition's telling him to beware Macduff. The witches are equivocating here, as Macbeth discovers in Act 5, scene 8. The bloody child's statement has a double meaning.
Macbeth tells Macduff, "I bear a charm'd life"; no one can kill him. To his shock, Macduff declares he was from his "mother's womb untimely ripp'd." Macduff was not born in the normal way; rather, he was born by Caesarean section: his mother's abdomen was cut open and the baby was removed from her body. Therefore, Macduff will be able to kill Macbeth.
At first Macbeth refuses to fight Macduff, but when Macduff threatens to humiliate Macbeth by parading him so that the "rabble" can taunt and curse him, Macbeth chooses to fight to the death.
The 'bloody child' is the second of the three apparations conjured up for Macbeth in act 4 sc.1. The apparition instils in Macbeth a stubbornness and a false sense of security by artful equivocation:
"Be bloody, bold and resolute; laugh to scorn
The power of man, for none of woman born
Shall harm Macbeth".
The 'bloody child' the infant Macduff as he looked, when cut out of the bleeding womb of its mother, and covered with blood. Earlier, the first apparition, 'an armed Head', warned Macbeth against the possible threat posed by Macduff. Macbeth found his own fear concerning Macduff echoed by the first Apparition. But Macbeth is unable to read into the equivocation of the second Apparition. Macbeth draws a simplistic conclusion that he is invincible, never to die in the hands of a man.
However, the mystery is unveiled when Macduff tells Macbeth how he was 'from his mother's womb/Untimely ripped'. Macbeth could understand that he has been deceived--'..be these juggling fiends no more believ'd'. Macduff was the man destined to overpower him.