Macduff is the archetype of the avenging hero, not simply out for revenge but with a good and holy purpose. Macduff is the character who has two of the most significant roles in the play: First, he is the discoverer of Duncan's body. Second, the news of the callous murder of his wife and children (Act IV, Scene 3) spurs him toward his desire to take personal revenge upon the tyrannical Macbeth. When he knocks at the gate of Macbeth's castle in Act II, Scene 3, he is being equated with the figure of Christ, who before his final ascension into Heaven, goes down to release the souls of the damned from hell (the so-called "Harrowing of Hell").