I believe that the murder of King Duncan was not Macbeth's fault- due to Macbeth's wife persuading him to murder Duncan for wealth, power and prosperity. Macbeth's wife character traits were: self-centred to herself, selfish to others for demand (taking advantage of Macbeth) to murder the innocent.
Due to Macbeth's wife unlawful desires and powerfulness to control her husband; Macbeth (perusing him to kill the innocent for power: Duncan, Banquo) thus, Macbeth's character traits have changed from coward, shy, fearful to greedy, self-centred, powerful and lustful like his wife: Lady Macbeth
Macbeth and lady Macbeth's notorious murder plan to kill Duncan was a success as grooms and servants were drunk on the scene, therefore, they couldn't watch the murders stab Duncan as he slept on his death bed.
Thus, due to Lady Macbeth's greed and selfishness to come to crown, Macbeth was hypnotized by lady Macbeth's charm and lust that in result would do anything to please his wife. Therefore, Macbeth's duty was to abolish the King and that's when his inner self changes..
