Through Shakespeare's soliloquies the audience hears the characters' inner most thoughts and desires. The audience learns the character's true feelings and intentions, which other characters in the play may not be aware of . Thus at times creating dramatic irony.
In "Macbeth" the audience learns that Macbeth's character may be brave and physically strong when on the battlefield, but he is also ambitious, selfish and morally weak. As can been seen in his soliloquy in Act 1 sc 7 where he contemplates the murder of Duncan. Though it does become evident that Macbeth possesses a conscience and knows right from wrong, he does not follow these considerations. Instead his reasoning for not killing Duncan is merely practical.
His main concern is that if he kills Duncan he may bring death upon himself establishing the idea of consequence. Macbeth feared that Duncan may "teach bloody instructions" so that others may "..return
to plague the inventor", if he killed the king then others could easily do the same to him if he were to succeed the throne.
The use of the word "assassination" is a political term suggesting that Macbeth's first objection to the murder of Duncan was not moral, but was practical.
Another of Macbeth's concerns is that by killing Duncan he may change his own fate of becoming king, as he realises that it is simply ambition that spurs him to murder Duncan and worries that his actions may start an unstoppable domino effect.
Finally Macbeth's morals do come through as he realises he will be murdering a good king and takes pity on him "like a naked new born babe... shall blow the horrid deed in every eye...". he recognises the importance of doing what is right, Macbeth realises he would be...