The line "fair is foul and foul is fair" is demonstrated in the entire play. Can you identify those instances?

When the Battle's Lost and Won

Macbeth is a play based on contradictions and equivocations. There is a contradiction on almost every page. I'm as sure as I can be that Shakespeare planned it that way. Indeed, the witches themselves rely on double meanings and contradictions all the time:

Lesser than Macbeth, and greater.

Not so happy, yet much happier.

Thou shalt get kings, though thou be none.

So all hail, Macbeth and Banquo!

Banquo and Macbeth, all hail!

Want more? Lady Macbeth asks to be unsexed and Macbeth later says to her:

Bring forth men-children only,

For thy undaunted mettle should compose

Nothing but males.

And she refers to him as a woman:

O, these flaws and starts,

Impostors to true fear, would well become

A woman's story at a winter's fire,

Authorized by her grandam.

More? The porter's speech before answering the knock the door is all contradictions:

Here's a farmer that hanged himself on th’ expectation of plenty...here's an equivocator that could swear in both the scales against either scale, who committed treason enough for God's sake yet could not equivocate to heaven...here's an English tailor come hither, for stealing out of a French hose...But this place is too cold for hell.

More? In Act 4, Scene 3, the entire first part of the conversation between Malcolm and Macduff is equivocation and contradiction. Malcolm is telling Macduff things about himself that are comletely opposite of the truth.

I could give you much more, but just know that the play, Macbeth, is based upon the idea that the world has been turned upside down: good is seen as evil, evil as good, men act like women, women act like men, truth is taken for lies and lies for truth, killing is good and then killing is bad, and so on and so on. "Fair is foul, and foul is fair," for sure and everywhere.

OK, here's one more in parting:

Angels are bright still, though the brightest fell.

Though all things foul would wear the brows of grace,

Yet grace must still look so.

Just open to any page and there they are, like bones that support the body.