I was watching Criminal Minds and this poem was mentioned. It is by William Wordsworth from Ode: Intimations of Immortality from Recollections of Early Childhood.
What though the radiance which was once so bright
Be now for ever taken from my sight,
Though nothing can bring back the hour
Of splendor in the grass, of glory in the flower;
We will grieve not, rather find
Strength in what remains behind;
In the primal sympathy
Which having been must ever be;
In the soothing thoughts that spring
Out of human suffering;
In the faith that looks through death,
In years that bring the philosophic mind.
I like the line "We will grive not, rather find Strength in what is left behind". It is easier to say then to actually do..