As foil to Macbeth and Lady Macbeth who both try to remove the eyes of heaven, invoke darkness and cut the very source of light, Macduff seeks his revenge in righteousness, invoking heaven in the act, embracing the divinity in his act of revenge. His murder of a king is thus separated from Macbeth's, an audience would have likely vouched, becoming quite boisterous in Macbeth's cathartic punishment beginning.