Considering that the second scene of Act II has an overall ominous mood, the nocturnal setting seems to fit perfectly. It is the very scene before Duncan is killed; therefore, Macbeth is becoming all the more affected by his ambition. It is also a night without the light of the moon as Fleance notes within the first few lines that "the moon is down." All of the characters, then, must carry torches (as the stage directions dictate). Throughout the scene it is most interesting to note the unnatural images in addition to those of both darkness and blood. For example, Macbeth soon sees a bloody dagger hovering before him. "Is this a dagger which I see before me, The handle toward my hand?" In addition to the ominous ghost-dagger, Macbeth speaks of "dudgeon gouts of blood" and "the bloody business" and how "nature seems dead”: all things that are out of the natural world, all greatly disturbing. This scene is truly a good precursor to Macbeth's evil deed.
Darkness is used by many authors to both increase the sense of foreboding and theme the of evil in a scene. Shakespeare does both in Act 2, scene 1 of "Macbeth". In the scene, both Banquo and Fleance are so disturbed they cannot sleep. As Banquo says, "Merciful powers/Restrain in me the cursed thoughts that nature/Gives way to in repose." In other words, the night and the chance to sleep are just magnifying his problems.After Banquo finally goes to bed, Macbeth sees a dagger in front of him. Once again the sense of foreboding is magnified. We know what Macbeth is contemplating and his casual talk with both Banquo and Fleance make his seem more heartless and evil. By the end of the scene, Macbeth goes off in darkness to kill Duncan. The darkness has reinforced the sense of evil surrounding Macbeth's intentions.