I like..

Elie Wiesel:
The opposite of love is not hate, it's indifference.
The opposite of art is not ugliness, it's indifference.
The opposite of faith is not heresy, it's indifference.
And the opposite of life is not death, it's indifference.

(1986)

Emily Dickinson:
If I can stop one heart from breaking,
I shall not live in vain.
If I can ease one life the aching,
Or cool one pain,
Or help one fainting robin
Unto his nest again,
I shall not live in vain.

Matthew Arnold:
Is it so small a thing
To have enjoy'd the sun,
To have lived light in the spring,
To have loved, to have thought, to have done...