Please explain this quote from Macbeth in detail:
Seyton—I am sick at heart, When I behold—Seyton, I say!—This push Will cheer me ever or disseat me now. I have lived long enough. My way of life(25) Is fall'n into the sear, the yellow leaf, And that which should accompany old age, As honor, love, obedience, troops of friends, I must not look to have; but, in their stead, Curses, not loud but deep, mouth-honor, breath,(30) Which the poor heart would fain deny and dare not.
Macbeth shouts for his servant Seyton to bring him his armor. He is anticipating the battle he is about to face against Malcolm and Macduff. He is sick in his heart. While he is believing the prophecy that no man born of woman can harm him, Macbeth is still sick at heart. He decides that this attack will determine the throne is his forever or this attack will dethrone him.
He muses at how withered his life has become:
Seyton! I am sick at heart, When I behold Seyton, I say!- This attack Will give me the throne forever or unseat me now. I have lived long enough. My way of life Is fallen into the dry, withered yellow leaf, And the things which should accompany old age, Honor, love, obedience, troops of friends, I think I’ll have, but, instead of them, I’ll have Curses, not loud, only deep, mouth-honor, breath, Which the poor heart would gladly deny, and dare not.
Macbeth is claiming that he will not be honored in old age. He will be cursed. He claims that the curses will be mouth-honor, which is honoring that is not truly meant from the heart, honoring that would be denied but some dare not for fear of Macbeth.
Macbeth has come to the end of his life. He has gained the throne only temporarily and what good is that? Macbeth is bitter.
Macbeth's wife has gone mad. His world is falling apart. He only progresses forward toward battle because he has some faith in the prophecy that states he cannot be harmed by man born of woman.
Little does he know at this point, but Macduff was not born of woman. He was brought into the world through cesarean birth.