At the play's end, everyone is ready to head back to Naples, where Miranda and Ferdinand will get hitched before old Prospero retires to Milan. (Good thing Prospero's big, nasty storm didn't actually destroy the ship, right?)
In the meantime, everyone leaves the stage and heads inside to Prospero's cell. But Prospero remains on stage and delivers one of the most fascinating and moving speeches in all of Shakespeare:
Now my charms are all o'erthrown,
what strength I have's mine own,
Which is most faint: now, 'tis true,
I must be here confined by you,
Or sent to Naples. Let me not,
Since I have my dukedom got
And pardon'd the deceiver, dwell
In this bare island by your spell;
But release me from my bands
With the help of your good hands:
Gentle breath of yours my sails
Must fill, or else my project fails,
Which was to please. Now I want
Spirits to enforce, art to enchant,
And my ending is despair,
Unless I be relieved by prayer,
Which pierces so that it assaults
Mercy itself and frees all faults.
As you from crimes would pardon'd be,
Let your indulgence set me free.
In other words, Prospero says that now that he's retired from a lifetime of performing magic, he needs the audience's help if he wants to leave the island—the only thing that can free him and send him home is the audience's approval and loud applause. That's weird, don't you think? Why the heck does Prospero need the audience's applause in order to return home?
Like we've said before, for some, this final speech is Shakespeare's way of saying goodbye to the theater. (The Tempest was probably the last play Big Willy wrote entirely himself and, soon after The Tempest was completed around 1611, Shakespeare left London and retired to Stratford.)
If we read Prospero the skillful magician as an artist like Shakespeare the skillful playwright, then we can see why the following lines might sound like a touching goodbye: " Now my charms are all o'erthrown, / what strength I have's mine own."
For more on Prospero's relationship to the magic of the theater, see "Quotes: Art and Culture."