The good news: Among even the most biblically impaired, the term "Good Samaritan" carries a full load of moral meaning. The bad news: Our assumed familiarity with this story's plot and players in many ways has tamed the radical message of Jesus' parable.

Choosing a Samaritan as the "good guy" is surprising, not only to the confident lawyer questioning Jesus; it also shocks his own disciples. Only a few pages back, Luke's gospel records how some Samaritans themselves had treated the prospect of a visit by Jesus and his disciples. In 9:51-56, Jesus' disciples are turned away from spending the night in a nameless Samaritan village. The Samaritans reject Jesus' messengers because they are on their way to Jerusalem. The enmity between Jews and Samaritans flowed in both directions.

Historically,…