Thou seest the heavens, as troubled with man’s act, / Threatens his bloody stage: by the clock ’tis day, / And yet dark night strangles the travelling lamp.
Act II, Scene 4
Context
Ross describes to the Old Man the unnatural darkness that persists even though it is daytime, following Duncan's murder the previous night.
Analysis
The verb 'strangles' transforms darkness into an active killer, mirroring how Macbeth has just murdered Duncan under cover of night. By having darkness literally choke the sun—'the travelling lamp'—Shakespeare makes the cosmic disorder feel physical and violent, not merely symbolic. This invites the audience to see regicide as an act so monstrous it infects the entire natural order, justifying the play's equation of political and cosmic law.
Essay Tip
Support a thesis that Shakespeare uses pathetic fallacy not just for atmosphere but to argue that legitimate kingship is part of natural law—when Macbeth breaks political order, he literally breaks nature itself, shown by darkness violently overpowering day.