In Shakespeare's "Macbeth," the vision of the banquet scene, particularly in Act 3, Scene 4, serves as a critical moment that underscores themes of guilt, ambition, and the psychological unraveling of the protagonist. During this scene, Macbeth, now crowned king, hosts a banquet for the lords of Scotland. However, his ambition and the murderous acts he has committed (including the killing of King Duncan and Banquo) haunt him.
The "blood line" reference is primarily related to Banquo’s lineage. The witches prophesied that Banquo's descendants would be kings, which deeply troubles Macbeth, who fears that his own power is threatened. In the banquet scene, Macbeth sees the ghost of Banquo seated at the table, an embodiment of his guilt and paranoia. This hallucination represents his inner turmoil and moral deterioration. Macbeth's vision of Banquo’s bloodline signifies the inescapable consequences of his ambition, suggesting that his actions will ultimately lead to his downfall.
The bloodline is also significant because it represents the idea of legacy and the natural order being disrupted. Macbeth's unlawful rise to power through murder ultimately sets in motion a series of events leading to his demise, reinforcing the theme that treachery and guilt cannot be escaped. The vision of Banquo at the banquet serves as a stark reminder of Macbeth's guilt and the futility of trying to escape fate—Banquo's line will prevail, even if Macbeth's reign is built on crime and bloodshed.