Paradoxes in Macbeth

After finishing reading Shakespeare's play Macbeth, I remembered how on the first day of looking at the text we briefly touched upon paradoxes within this play. flipping to the first pages of the play (where I wrote the definition) I began looking for some. Within the first page I stumbled across line 12 of Act 1, scene 1: "fair is foul, and foul is fair". While this qualifies as a paradox, how does it relate to the play? and how did it, if at all, foreshadow any of the events that occurred in this tragedy. First off, this paradox means that while some things may appear to be great (fair), they can really be concealing their evil (foul). From this, the immediate example that came to mind was of how this paradox directly correlates with King Duncan and Macbeth. While by merely looking at him and his achievements, Duncan came to the conclusion that Macbeth was this amazing war hero (fair). However, with absolutely no suspicion on Duncan's part, Macbeth show his evil capability (foul) to kill him and claim the throne. From this small paradoxical phrase that kicks off the play, Shakespeare is able to build an entire play of this simple, yet critical motif.