The title of the poem is, of course, a reference to Shakespeare's play Macbeth. The following quotation is from Act 5, Scene 5
To-morrow, and
to-morrow, and
to-morrow,
Creeps in this
petty pace from day to day
To the last
syllable of
recorded time,
And all our
yesterdays have lighted
fools
The way to dusty
death. Out, out, brief candle!
Life's but a walking
shadow, a poor
player
That
struts and
frets his
hour upon the stage
And then is heard no more: it is a
tale
Told by an
idiot, full of
sound and fury,
Signifying nothing.
It was also suggested to me that Frost may have also been thinking of this quote from Act 5 Scene 1, made by Lady Macbeth
Out, damned spot! out, I say!--One: two: why,
then, 'tis time to do't.--
Hell is murky!--
Fie, my
lord, fie! a soldier, and afeard? What need we
fear who knows it, when none can call our
power to
account?--Yet who would have thought the old man
to have had so much
blood in him.