Please explain this quote from Shakespeare's Macbeth.
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,
This famous speech occurs in Act V, Scene 5, when Macbeth is awaiting the battle that will prove his undoing. He has just learned that his wife has committed suicide, consumed by guilt, and his response is a remarkably bleak reflection on life. "Tomorrow, and tomorrow, and tomorrow" evokes the relentless, numbing "petty" pace at which the days go by. Macbeth says that life is simply a march to our deaths, with no more meaning. He compares life first to a play, in which we are just actors that pass briefly upon the stage, and then to a "tale/Told by an idiot" which, for all its "sound and fury" has no deeper or lasting meaning. This is a profoundly bleak view of life, one which is held by a man who has, turned his back on his own humanity to fulfill his ambitions, and is about to be destroyed himself.