The king of Scotland should be a figurehead of order and orderliness, and Duncan is the epitome, or supreme example, of this. His language is formal and his speeches full of grace and graciousness, whether on the battlefield in Act I, Scene 2, where his talk concerns matters of honor, or when greeting his kind hostess Lady Macbeth in Act I, Scene 6. Duncan also expresses humility (a feature that Macbeth lacks) when he admits his failure in spotting the previous Thane of Cawdor's treachery: "There's no art to find the mind's construction in the face" (I: 4,11).
Most importantly, Duncan is the representative of God on earth, ruling by divine right (ordained by God), a feature of kingship strongly endorsed by King James I, for whom the play was performed in 1606. This "divinity" of the king is made clear on several occasions in the play, most notably when Macbeth talks of the murdered Duncan as having "silver skin lac'd with . . . golden blood" (Act II, Scene 3). The importance of royal blood, that is, the inheritance of the divine right to rule, is emphasized when, in the final scene, Duncan's son Malcolm takes the title of king, with the words "by the grace of Grace / We will perform."