In Shakespeare's tragedies often the main character is given a chance to say something significant before he dies. What speech might function as Macbeth's farewell even though it doesn't occur in act?

Macbeth's final soliloquy in Act V, Scene 5 ("Tomorrow and tomorrow and tomorrow") can be considered as his farewell speech as it reflects on the meaningless nature of life and his impending death. This soliloquy encapsulates Macbeth's despair and nihilism as he realizes the futility of his actions and the inevitability of his downfall.