The lines that Macbeth speaks to his wife about sleep are among the most beautiful Shakespeare ever wrote. Here they are in full:
Me thought I heard a voice cry “Sleep no more!
Macbeth doth Murder sleep”—the innocent sleep,
Sleep that knits up the ravell'd sleave of care,
The death of each day's life, sore labor's bath,
Balm of hurt minds, great nature's second course,
Chief nourisher in life's feast—
What do you mean?
Still it cried, “Sleep no more!” to all the house;
“Glamis hath murdered sleep, and therefore Cawdor
Shall sleep no more. Macbeth shall sleep no more.”
The whole play, like all Shakespeare's plays, is written in poetry recited by the various characters. Shakespeare's poetry, it should go without saying, is what is best in Shakespeare. Shakespeare's poetry is Shakespeare. Here Macbeth is quoting a voice he thought he heard. He says it cried "Sleep no more!" to all the house. That seems intended to answer the question of why he doesn't...
(The entire section contains 826 words.)