Duncan's speech on his arrival at Inverness is heavy with dramatic irony: Not only is the "seat" (the surroundings) of the castle "pleasant," but even the air is sweeter than that to which the king is accustomed. The presence of the martlet (a summer bird) serves to heighten the irony. As far as the king is concerned, the castle, from the outside at least, appears to be a paradise. Contrast this picture of delight with the imagery of hell that forms the substance of the Porter scene (Act II, Scene III).
The king's address to Lady Macbeth and her subsequent reply are full of the heightened language of formal introduction: "God ‘ild you," "We rest your hermits (your servants) ever." Of course, her elaborate greeting contrasts her language of the previous scene and emphasizes her falsity.
The stage directions that frame this scene are full of the pomp and ceremony of a royal visit. To a musical accompaniment, food and drink are transported from one side of the stage to the other. Although the audience does not see the revelry on stage, Shakespeare intends us to understand that the king is to be well entertained.
