Shakespeare on Prayer - Prospero's Speech

From the end of The Tempest:

Now my charms are all o'erthrown,
And 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.