These words are uttered by Macbeth after he hears of Lady Macbeth’s death, in Act 5, scene 5, lines 16–27. Given the great love between them, his response is oddly muted, but it segues quickly into a speech of such pessimism and despair—one of the most famous speeches in all of Shakespeare—that the audience realizes how completely his wife’s passing and the ruin of his power have undone Macbeth. His speech insists that there is no meaning or purpose in life. Rather, life “is a tale / Told by an idiot, full of sound and fury, / Signifying nothing.” One can easily understand how, with his wife dead and armies marching against him, Macbeth succumbs to such pessimism. Yet, there is also a defensive and self-justifying quality to his words. If everything is meaningless, then Macbeth’s awful crimes are somehow made less awful, because, like everything else, they too “signify nothing.”
I know that you said 'opening line', but I found all of that information kind of hard to fit into a handful of sentences. As a result, what I've written might really differ from your perceptions of the story. I hope that it's not too different and that it works for you. Good luck.
