Simon Wiesenthal, who died recently at 96, did the human race a great service by not allowing us to forget the victims of the Holocaust and the horrendous evils perpetrated by the Nazis.

Serious evil must never be excused, condoned, or shrugged off. By playing a vital role in tracking down and bringing to justice about 1,100 perpetrators of genocide, Wiesenthal made us take seriously the ever-present possibility of society slipping into hell.

In 1969, Wiesenthal published The Sunflower, in which he related a thought-provoking incident. A 22-year-old SS trooper who was dying with a troubled conscience asked Wiesenthal as a Jew for forgiveness for his part in the genocide. The young man had participated in shooting Jews who were fleeing a burning building. Wiesenthal left the room in stony silence, refusing to speak a word of forgiveness. Later, during his long career reminding the world of Nazi atrocities, Wiesenthal said, "If we pardon this genocide, it will be repeated and not only on Jews. If we don't learn this lesson, then millions died for nothing."

Did Wiesenthal do the right thing? In subsequent editions of The Sunflower, leading Jewish and Christian thinkers commented on the Nazi's request and the future Nazi-hunter's refusal. In "The Virtue of Hate" (First Things, February 2003), Meir Soloveichik argued that Judaism and Christianity are fundamentally defined by their seminal moments: Judaism, by the giving of the covenant law at Sinai; Christianity, by the sacrifice of Jesus on Calvary. Forgiveness permeates both the vertical and horizontal dimensions of Christian spirituality.

Though Soloveichik drew too sharp a line between the theologies of Judaism and Christianity, our different approaches to forgiveness are certainly ...