Act II Scene i

QUESTION: How does the imagery night reflect the event in the plot?

In Act II, Scene i, before the conspirators come, Brutus paces the floor during the night, saying,

"Since Cassius first did whet me against Caesar, I
have not slept.
Between the acting of a dreadful thing
And the first motion, all the interim is
Like a phantasma, or a hideous dream"

“Let'em enter.
They are the faction. O conspiracy,
Sham's thou to show thy dang'rous brow by night, When
evils are most free? O, then by day
Where wilt thou find a cavern dark enough
To mask they monstrous visage? Seek none, conspiracy; Hide
it in smiles and affability:
For if thou path, thy native semblance on,
Not Erebus itself were dim enough
To hide thee from prevention.”