This is a favorite poem of mine–I have it almost by heart; but I did Google it to make sure and found it on a wonderful website with a collection of quotations and other resources for those who are grieving the loss of a loved one.
Remember me when I am gone away,
gone far away into the silent land;
when you can no more hold me by the hand,
nor I half turn to go, yet turning stay.
Remember me when no more day by day
you tell me of our future that you planned:
only remember me; you understand
it will be late to counsel then or pray.
Yet if you should forget me for a while
and afterwards remember, do not grieve:
for if the darkness and corruption leave
a vestige of the thoughts that once I had,
better by far you should forget and smile
than that you should remember and be sad.
—Christina Rossetti (1830-1894)