The Moment Before Murder
Lady Macbeth's advice to "look like th'innocent flower, but be the serpent under't" perfectly captures the theme of appearance versus reality. This deception becomes Macbeth's way of life after Duncan's murder.
Duncan's ironic comment that the castle "hath a pleasant seat" creates dramatic tension - the audience knows he's walking into his death whilst praising his future murder scene. Shakespeare uses this irony to build suspense.
Macbeth's moral struggle peaks in his "If it were done when 'tis done" soliloquy. He lists reasons against the murder: Duncan is his kinsman, subject, and guest. The phrase "double trust" emphasises how deeply he'll betray Duncan.
His conclusion that he has "no spur to prick the sides of my intent, but only vaulting ambition" shows remarkable self-awareness. He knows ambition is his only motive, and he recognises it will ultimately destroy him.
Essay Gold: This soliloquy is perfect for exploring Macbeth's character - he's not evil, just fatally ambitious and weak-willed.