What does the theme 'Appeareance and reality' have to do with Macbeth, and how does he show this in his soliloquies?

Appearance and reality is an extremely important theme from the play.  The first example we see is in Lady Macbeth's plans to murder Duncan.  She dictates to Macbeth, look like the innocent flower, But be the serpent under't. (I.v.75) Lady Macbeth knows that Macbeth needs instruction in how to maintain the appearance of innocence as he plots and executes Duncan's murder (she believes he has a weaker "nature" than she does); the reality of the situation is that Lady Macbeth and Macbeth have murderous intents, so Macbeth may take over the crown. After the murder, Macbeth appears to be horrified and devastated by the crimes when, in reality, he is the perpetrator.  

As the play continues, Macbeth continues to maintain false appearances.  He portrays himself as a loyal friend to Banquo while he secretly plans his murder.  Most kinsmen believe Macbeth to be a strong, loyal, intelligent, virtuous ruler who has earned his titles through his merit while the reality is that Macbeth has violently and dishonestly moved up in rank after his last earned title of Thane of Cawdor. One major lesson to be learned from Macbeth: things are almost never how they appear!