Macbeth was a play written especially for James I and although, historically, the "real" Macbeth was nothing like Shakespeare's Macbeth, there were some similarities with the King of Scotland and James I could trace his line back to Banquo. Shakespeare was fully aware of his obligations towards his king
keenly aware of his audience and his political responsibilities.
From the first time we meet Macbeth, appearance and reality are already causing confusion. "So foul and fair a day I have not seen,"(I.iii.38) says Macbeth which already foreshadows what is to come as "foul" becomes "fair" and vice versa.
Appearance and reality is a common literary theme of the time and Macbeth has it in abundance as times were hard and a chance to escape reality was welcomed. Furthermore, there were many for whom appearance and reputation controlled all their actions, belying what lay beneath the surface.
"nothing is / But what it is not" (I.iii.141-142).
Macbeth needs Lady Macbeth at the beginning to give him the apparent "manliness" he lacks. Unfortunately, he ultimately withdraws from Lady Macbeth as the more he
pursues his ideal understanding of manliness—.....- the less humane he becomes
Macbeth's impatience and his need (and that of Lady Macbeth) to ensure the fulfillment of the prophesies, prevent the normal passage of time during which the prophesies could have been expected to come true.
Typical of the era, Macbeth will finally become a tragic hero as he cannot fight the forces of evil and his fatal flaw, his "vaulting" ambition provide the opening for sympathy towards him. The play will close with order restored and the rightful heir in place.
Audiences of the day could go home satisfied that good triumphs over evil and having the rightful king in his seat shows that justice does prevail.