My wife and I recently watched Bonhoeffer: Pastor. Spy. Assassin., a movie that I would recommend. An alternate title could have been, Dietrich Bonhoeffer Changes His Theology about Nonresistance.
Along those lines, I’ve got some food for thought for those who believe that the early church universally held to an Anabaptist view of nonresistance—the idea Christians should never physically do anything to defend themselves or others (the latter of which many of us consider to be a transgression of the commandment to love our neighbors as ourselves).