John MacArthur calls Matthew 7:21 the most terrifying verse in the Bible. "Not everyone who says to Me, 'Lord, Lord,' will enter the kingdom of heaven." Clearly, some people are convinced they are Christians when, in fact, they are still lost in their sin. How can you be sure your salvation is real? Find out in this episode, as Dr. Abner Chou and Dr. Nathan Busenitz explore the doctrine of assurance.