Can it be right to give what I can give ?
To let thee sit beneath the fall of tears
As salt as mine, and hear the sighing years
Re-sighing on my lips renunciative
Through those infrequent smiles which fail to live
For all thy adjurations ? O my fears,
That this can scarce be right ! We are not peers,
So to be lovers; and I own, and grieve,
That givers of such gifts as mine are, must
Be counted with the ungenerous. Out, alas !
I will not soil thy purple with my dust,
Nor breathe my poison on thy Venice-glass,
Nor give thee any love--which were unjust.
Beloved, I only love thee ! let it pass.

Elizabeth Barrett Browning

http://www.poemhunter.com/poem/sonnet-ix-3/