Act 3, Scene 1
Alone at Macbeth's court, Banquo voices his suspicions that Macbeth has killed Duncan in order to fulfill the witches' prophesies. He muses that perhaps the witches' vision for his own future will also be realized, but pushes the thought from his mind. Macbeth and Lady Macbeth enter to the fanfare of trumpets, along with Lennox and Ross. Macbeth announces that he will hold a banquet in the evening and that Banquo will be honored as chief guest. Banquo states that he must ride in the afternoon but will return for the banquet. Macbeth tells him that Malcolm and Donalbain will not confess to killing their father. After confirming that Fleance will accompany Banquo on his trip, Macbeth wishes Banquo a safe ride.
Left alone, Macbeth summons the two murderers he has hired. While he waits for them, he voices his greatest worry of the moment—that the witches' prophecy will also come true for Banquo, making his children kings. He will put an end to such worries by hiring two men to kill Banquo and Fleance. The men are not professional assassins, but rather poor men who are willing to work as mercenaries. Macbeth has already blamed their current state of poverty on Banquo. He now tells them that while Banquo is his own enemy as much as theirs, loyal friends of Banquo's prevent him from killing Banquo himself. Macbeth proceeds to detail the particulars of the murder: they must attack him as he returns from his ride—at a certain distance from the palace—and they must also kill Fleance at the same time.
Act 3, Scene 2
Alone on stage, Lady Macbeth expresses her unhappiness: there seems to be no end to her desire for power and she feels insecure and anxious. Macbeth enters looking upset and she counsels him to stop mulling over the crimes they have committed. But Macbeth declares that their job is not done: he still spends every waking moment in fear and every night embroiled in nightmares. He even envies Duncan, who now sleeps peacefully in his grave. Lady Macbeth warns him to act cheerful in front of their dinner guests. She also tries to comfort him by reminding him that Banquo and Fleance are by no means immortal. Macbeth responds by telling her that "a deed of dreadful note" will be done in the night, though he will not divulge the details (33).
Act 3, Scene 3
The two murderers are joined by a third, who says that he has also been hired by Macbeth. Horses are heard approaching and Banquo and Fleance enter. The murderers attack Banquo but Fleance manages to escape. The murderers leave to report back to Macbeth.
Act 3, Scene 4
At the banquet, a murderer arrives and reports to Macbeth just as the dinner guests begin to arrive. He informs Macbeth that Banquo is dead but Fleance has escaped. Shaken, Macbeth thanks him for what he has done and arranges another meeting on the following day. The murderer leaves and Macbeth returns to the feast.
Looking over the table, Macbeth declares that the banquet would be perfect if only Banquo were present. At this point Banquo's ghost appears unobserved and takes Macbeth's seat. The guests urge Macbeth to sit and eat with them but Macbeth says that the table is full. When Lennox points to Macbeth's empty seat, Macbeth is shocked to see Banquo’s ghost. He addresses the ghost, saying, "Thou canst not say I did it. Never shake / Thy gory locks at me" (49-50). The guests, confused by his behavior, think that he is ill. Lady Macbeth reassures them, however, by saying that he has had similar fits since youth and that he will soon be well. She draws Macbeth aside and attempts to calm him by asserting that the vision is merely a “painting of [his] fear”—just like the dagger he saw earlier (60). Ignoring her, Macbeth charges the ghost to speak but it disappears. After Lady Macbeth scolds him for being "unmanned in folly" (73), Macbeth returns to his guests and claims that he has "a strange infirmity," which they should ignore (85).
Just as the party resumes and Macbeth is offering a toast to Banquo, the ghost reappears. As Macbeth once again bursts out in a speech directed at the ghost, Lady Macbeth tries to smooth things over with the guests. In response to Macbeth’s exclamation that he sees sights that make his cheeks “blanched with fear,” Ross asks what sights Macbeth means (114). Lady Macbeth asks the guests to leave, since Macbeth's "illness" seems to be deteriorating. Alone with Lady Macbeth, Macbeth expresses his deep anxieties and vows to return to the Weird Sisters.
Act 3, Scene 5
On the heath, the witches meet Hecate, queen of witches, who chastises them for meddling in Macbeth's affairs without involving her or showing him any fancy magic spectacles. She tells them that Macbeth will visit them tomorrow and that they must put on a more dramatic show for him.
Act 3, Scene 6
Lennox and another lord discuss politics. Lennox comments sarcastically on the recent deaths of Duncan and Banquo. He suggests that it seems implausible for Malcolm and Donalbain to be inhuman enough to kill their father. Moreover, Macbeth's slaying of the bodyguards seemed very convenient, since they probably would have denied killing Duncan. Lennox proposes that if Malcolm, Donalbain, and Fleance were in Macbeth's prison, they would also probably be dead now. He also reveals that since Macduff did not attend Macbeth's feast, he has been denounced. The lord with whom Lennox speaks comments that Macduff has joined Malcolm at the English court. The two men have apparently asked Siward to lead an army against Macbeth. Lennox and the lord send their prayers to Macduff and Malcolm.
The “be a man” theme recurs in Macbeth’s address to the murderers. When Macbeth demands whether the murderers have the courage to kill Banquo, they answer "we are men, my liege" (III i 92). But their answer does not satisfy Macbeth, who berates them as less-than-exemplary examples of men. Macbeth thus uses very much the same goading tactics his wife used in compelling him to kill Duncan. But what does it mean, exactly, to “be a man”? Both Macbeth and his Lady seem to have a clear idea of properly masculine actions. In Act 1, Lady Macbeth suggests that masculinity is largely a question of ruthlessness: one must be willing to “das[h] the brains out” of one’s own baby (58). She claims that she herself is less "full o' th' milk of human kindness" than Macbeth—that is, more capable of casting away the last shreds of compassion, tenderness, loyalty, and guilt.
Lady Macbeth is not the only character that values ruthlessness as a masculine trait. Duncan, too, evaluates heroic action on a rather gory scale. When the captain describes how Macbeth “unseamed [Macdonald] from the nave to th’ chops” with “his brandished steel / Which smoked of bloody execution,” Duncan responds with high praise: "O valiant cousin, worthy gentleman" (I ii 17-22)! A "real man” in Macbeth, then, is one who is capable of copious bloodshed without remorse. The catch, of course, is that the bloodshed must be justified. Whereas Macbeth needs no reason to slay Macdonald in battle per se, the two murderers require the justification that Banquo is an evil man.
As for the terms of murder, Macbeth warns the murderers to kill Fleance and thus “leave no rubs nor botches in the work" (III i 135). Macbeth "require[s] a clearness”—that is, a clearance from suspicion but also a mental and physical cleanliness. The theme of stains and washing runs throughout the play. From Macbeth's cry about all “great Neptune’s ocean” in Act 2, to his instructions to the murderers in Act 3, to Lady Macbeth's famous “Out, damned spot" speech in Act 5, the Macbeths are haunted by the idea that they will be forever stained. Even when Macbeth has Banquo killed at a safe distance from himself, the spilled blood still returns to haunt Macbeth. When the murderer shows up to report his success, Macbeth observes: "There's blood upon thy face" (III iv 11). The blood itself serves a sign and reminder of the Macbeths’ culpability—ultimately driving Lady Macbeth mad.
Banquo's murder itself makes use of a common theme in Shakespeare's plays: the contrast between light and dark. While the murderers wait for Banquo and Fleance to approach, one of them observes that the sun is setting. This is no coincidence: Banquo serves as a bright contrast to the dark night that accompanies Macbeth's rise to power. He is a man who does not allow his ambitions to eclipse his conscience. At the moment that he dies, therefore, it is appropriate for the last remnant of sunlight to fade away. Such symbolism is reinforced by the fact that Banquo and Fleance approach the murderers carrying a torch. The torchlight is the first thing that the murderers see: "a light, a light" notes the second murderer (III iii 14). And after the deed is finished, the third murderer asks: "who did strike out the light?" (III iii 27). At the same moment that the good and kind Banquo dies, the light is extinguished.
Another aspect of Banquo's murder has intrigued generations of scholars: who is the third murderer? Some believe that it is Lady Macbeth, who expressed curiosity about Macbeth’s plans in Scene 2. Others believe that it is Macbeth himself, who could not trust the murderers fully. The third murderers could even be the three witches in disguise. In any case, introducing a third murderer rounds out the number of murderers so that they balance the three witches. There is power in the number three: Macbeth meets three witches, commits three separate murders, and sees three apparitions. The number three recurs throughout the play, adding to its mysterious and magic atmosphere
Finally, one of the most compelling scenes in Macbeth takes place at the banquet haunted by Banquo's ghost. Once again, the boundaries between reality and the supernatural are blurred as Banquo's ghost appears twice—both at exactly the moment Macbeth mentions him. It seems that the vision of Banquo accompanies the idea of Banquo in Macbeth’s mind. The ghost thus seems more like the manifestation of an idea—a figment of the imagination—rather than a “real” ghost. Lady Macbeth says as much when she pulls Macbeth aside: “This is the very painting of your fear; / This is the air-drawn dagger which you said / Led you to Duncan" (III iv 60-62). Just like the dagger, Banquo's ghost appears to be a realization of Macbeth's guilt. Even if the occurrence is supernatural, the event is very real for Macbeth.