Shakespeare's sonnet 16

Let me not to the marriage of true minds
Admit impediments. Love is not love
Which alters when it alterations finds,
Or bends with the remover to remove:
O no! it is at ever-fixed mark
That looks on tempest and is never shaken;
It is the star to every wandering bark,
Whose worth`s unknown, altough his height be taken.
Love`s no 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 write, nor no man ever loved.