Some of us can learn mercy by reading about it in the Bible. Many more of us, however, learn mercy by taking the plunge and doing it.

Such was the case with Sister Helen Prejean. Her story is told in the book Dead Man Walking, which recently came out in film. Sister Helen hears one day of a correspondence program with prisoners on death row. She decides to participate and begins writing, even though she's been told not to expect to hear anything in return. Much to her surprise, though, one of the prisoners does respond and catches her completely off guard by asking her to be his spiritual guide. Apparently his execution date was fast approaching, and he wanted some representative of God to be there for support over the next several weeks.

Sister Helen hesitates. It is one thing to do cha…