When Macbeth is visited by the ghost of Banquo, it is a pivotal scene in Macbeth. It shows that Macbeth is feeling guilt, and that he is beginning to crack up. As a result, he goes on a murderous rampage and kills Macduff’s family.
Macbeth is enjoying himself before the feast. He is king, and he has taken care of Banquo. He has not a care in the world. Unfortunately, his conscience starts to bother him.
The time has been,
That, when the brains were out, the man would die,(95)
And there an end; but now they rise again, (enotes etext p. 51)
It’s all downhill from there. Macbeth’s ranting about the table being full and “gory locks” leads the dinner guests to assume that he is not well. Lady Macbeth covers for him, saying he’s suffered from these fits since he was a child, but she also admonishes him to get a hold on himself. It doesn’t work, and the party ends abruptly when Macbeth asks the guests why they aren’t bothered by “such sights.”
As a result of Banquo’s ghost’s visit, Macbeth determines that he has not killed enough people yet. His terrible and senseless slaughter of the Macduff family finally spurs Malcolm and Macduff to act, and they come for Macbeth and take him out.