In Act II scene 3 Lennox and Macduff come to Macbeth's castle, Inverness, very early in the morning to pick up the king. They have the duty of picking up the king as he has planned to leave at daybreak. Lennox asks Macbeth a seemingly simple question.
Does the king go hence today?
Macbeth's response on the surface seems to be in agreement;yes the king is supposed to be leaving today, but Shakespeare's clever word play reveals much more. Macbeth tells Lennox that yes the king is leaving today, as was the king's plan. But, as the audience knows, King Duncan has "left" in another way. As Macbeth as killed the king, Macbeth has ensured that he will leave, and is in fact already gone.