St. Paul quotes Joel that all who call upon the Lord will be saved. Did the Old Testament prophet Joel mean everyone or just the Jews? Building upon other OT prophesies, St. Paul emphasizes that for a person to call upon the Lord, that person must first believe the gospel, and for them to believe they must hear, and for them to hear someone must preach. But can just anyone decide that they are called to preach? And how can one know whether what one is preaching or hearing is true? This all has to do with being sent.