Repentance is a change mind, choosing to hate sin and love God, which radically alters our lives and makes us holy in conduct. It is also the missing half of the Christian message: Jesus went around teaching "repent and believe in the gospel" (Mark 1:15). If a person has not repented, then he is not a Christian, no matter what he says. We offer these resources to reintroduce this long-forgotten truth to the Church.