Religious Tolerance has information and quotations on the Ethics of Reciprocity and the Golden Rule.
Buddhism is well known as a religion that calls for compassion. The Dalai Lama has written a practical book on the subject, An Open Heart: Practicing Compassion in Everyday Life (New York: Back Bay Books, 2002).
On The Compassion Fatigue Awareness Project website, take a test to see if you are experiencing compassion fatigue, and find resources for recovery.
"Cells That Read Minds" (New York Times, Jan. 10, 2006) is an easy-to-read article on mirror neurons. "Role of Mirror Neurons May Need Rethink" (New Scientist, May 2009) offers a counter-argument to the prevailing understanding of mirror neurons.