Playwright Matthew Lopez discovered a surprising parallel in U.S. history: the Jewish Passover took place the same week the Civil War ended. Like the Jews leaving Egypt, African-American slaves were set free. Caleb De Leon, a Southern Jew, comes home to a plantation in ruins. Old Simon and young John, former slaves who adopted their master's faith, remain behind, asking "were we Jews, or were we slaves?" The answers (which come late and too hastily) are devastating. Whipping Man has the makings (a boffo amputation scene), but talk and exposition dominate. The cast, directed by Giovanna Sarcelli, makes the most of the strong moments. Avery Glymph's John has the most range, from sly humor to flashing anger. Underwritten Caleb is the play's dartboard, growing more and more evil. Mark J. Sullivan, whether screaming in pain or anger, rarely rises above rant. Though he had trouble with his lines when I saw the show, Charlie Robinson gave Simon a dearly earned stability, marbled with wisdom, as when he tells John, "You don't lose your faith by askin'. You lose your faith by not askin'."