Answer: This excerpt is part of a soliloquy that reveals Macbeth's inner conflict. The last line refers to the theme of fate versus free will.
Explanation: To identify the meaning of any given individual excerpt it is key to look at that excerpt in context and try to use those contextual clues to help us grasp it. This excerpt is actually from Act I scene 3 and is said by Macbeth as part of an aside in response to hearing the prophecy of the witches and then having the first element of that prophecy completed through his gaining of the title of Thane of Cawdor. In this aside, Macbeth explores his curious span of feelings at having had the first stage of the prophecy confirmed, and debates whether the prophecies he has received are good or bad.
Macbeth is asking if the prophecies are good, why is it that he finds himself observing killing King Duncan, something that terrifies him incredibly because it is such an unnatural thing to want to do? This excerpt therefore points towards the way in which Macbeth is already contemplating committing regicide to gain the crown for himself.
This excerpt is part of a soliloquy that reveals Macbeth's INNER CONFLICT. He is hesitant to go ahead with the crime. The last line refers to the theme of APPEARANCE VERSUS REALITY
