The service and the loyalty I owe,
In doing it, pays itself. Your highness’ part
Is to receive our duties; and our duties
Are to your throne and state children and servants,
Which do but what they should, by doing every thing
Safe toward your love and honour.

– William Shakespeare

Macbeth, Act 1, Scene 4. Macbeth pledges his loyalty to King Duncan and assures him that he will do everything he can to protect him. Of course Macbeth soon does the very opposite when he invites Duncan to his castle. In this passage Macbeth presents himself to the King as a patriot, saying that the chance to serve him is its own reward. There is an example of both dramatic irony and deception, since the audience knows that Macbeth wants to kill Duncan and become king himself.