Shakespeare's Sonnet_116

Let me not to the marriage of true
minds
Admit impediments. Love is not love
Which alters when it alteration finds,
Or bends with the remover to remove:
O no! It is an ever-fixèd mark
That looks on tempests and is never
shaken;
It is the star to every wandering bark,
Whose worth's unknown, although his
height be taken.
Love's not Time's fool, though rosy lips
and cheeks
Within his bending sickle's compass
come:
Love alters not with his brief hours and
weeks,
But bears it out even to the edge of
doom.
If this be error and upon me proved,
I never writ, nor no man ever loved.
–William Shakespeare

Ref: http://en.m.wikipedia.org/wiki/Sonnet_116