Thunder. [Enter] Third Apparition, a child crowned, with a tree in his hand

MACBETH                  What is this,

That rises like the issue of a king,

And wears upon his baby brow the round

And top of sovereignty?

ALL WITCHES            Listen, but speak not to’t.

THIRD APPARITION  Be lion-mettled, proud, and take no care

Who chafes, who frets, or where conspirers are.

Macbeth shall never vanquished be until

Great Birnam Wood to high Dunsinane hill

Shall come against him.

Descend                                              (4.1.84-92)

The first of the three apparitions to be crowned; so that’s what’s at stake. Macbeth underscores it in case the audience hasn’t spotted it, commenting not on the tree but on the crown, the round and top of sovereignty, on the baby brow (babies, again; this clearly isn’t a baby but it’s a reminder of babies more generally, and perhaps of Banquo’s Fleance as a future heir) of the child that rises like the issue of a king. You’re not allowed to ask anything, the witches remind him, Listen, but speak not to’t. This apparition, too, seems to reassure Macbeth, to give him courage: be lion-mettled, proud, and take no care who chafes, who frets, or where conspirers are. Don’t worry about what anyone’s saying, or plotting, don’t take any notice of the grumblers, or make any effort to stay on side with people. You’re the big man! Bit of swagger, lordly, king of the beasts. No one can beat Macbeth until great Birnam Wood to high Dunsinane hill shall come against him. Which is, like, never? A moving forest? (And one, incidentally, that would need to travel a considerable distance, about 12 miles, not that a London audience, or Shakespeare himself, would likely know that.) Third Apparition out, done, and all sounds and seems good.