William Shakespeare: Two Gentlemen of Verona, Act II, Scene VI

To leave my Julia, shall I be forsworn;
To love fair Silvia, shall I be forsworn;
To wrong my friend, I shall be much forsworn;
And even that power which gave me first my oath
Provokes me to this threefold perjury;
Love bade me swear and Love bids me forswear.
O sweet-suggesting Love, if thou hast sinned,
Teach me, thy tempted subject, to excuse it!
At first I did adore a twinkling star,
But now I worship a celestial sun.
Unheedful vows may heedfully be broken,
And he wants wit that wants resolved will
To learn his wit to exchange the bad for better.
Fie, fie, unreverend tongue! to call her bad,
Whose sovereignty so oft thou hast preferr'd
With twenty thousand soul-confirming oaths.
I cannot leave to love, and yet I do;
But there I leave to love where I should love.
Julia I lose and Valentine I lose:
If I keep them, I needs must lose myself;
If I lose them, thus find I by their loss
For Valentine myself, for Julia Silvia.
I to myself am dearer than a friend,
For love is still most precious in itself;
And Silvia—witness Heaven, that made her fair!—
Shows Julia but a swarthy Ethiope.
I will forget that Julia is alive,
Remembering that my love to her is dead;
And Valentine I'll hold an enemy,
Aiming at Silvia as a sweeter friend.
I cannot now prove constant to myself,
Without some treachery used to Valentine.
This night he meaneth with a corded ladder
To climb celestial Silvia's chamber-window,
Myself in counsel, his competitor.
Now presently I'll give her father notice
Of their disguising and pretended flight;
Who, all enraged, will banish Valentine;
For Thurio, he intends, shall wed his daughter;
But, Valentine being gone, I'll quickly cross
By some sly trick blunt Thurio's dull proceeding.
Love, lend me wings to make my purpose swift,
As thou hast lent me wit to plot this drift!