The second witch in Macbeth says, "When the hurly burly's done, when the battle is lost and won." Explain what is won and lost with reference to...

As noted above, the literal battle that the witches
discuss is the war between Scotland and Norway.  Duncan's army has been dispatched to
fight against the Norweyan army, and later the audience finds out that Banquo and
Macbeth have played major roles in the battle.  The witches always speak in paradoxes,
and the above quotation is an example of one:  "When the battle is lost and won."  On a
first reading, it seems impossible for a battle to be both lost and won, but perspective
proves the statement to be true:  one side of the battle will win, while the other will
lose.  In this case, Scotland came out of the battle victorious over Norway.  And the
witches do meet once the battle is over when they are confronted by Macbeth and Banquo
who are on their way home from the war.

Figuratively
speaking, the hurly-burly refers to the moral battles that will continue to wage
throughout the course of the play.  The witches meet again when Macbeth goes to see them
to get more answers about the safety of his place as King.  At this point, it seems that
Duncan has "lost" while Macbeth has "won," but the sides of good and evil are not so
clear.