How did Paul identify the “super-apostles” and their gospel as false? How can I identify a false Jesus, a false Spirit, and a false gospel? The Corinthian congregation did not have a New Testament as I do. Most had not been written down in a codex (the precursor to the bound book). They did have Paul’s letters like 1 & 2 Thessalonians, James’ letter, and the apostles’ verbal teachings relaying what Jesus taught. The gospels were still being written. Paul wanted them to weigh the “super-apostles” teachings against the ones the apostles were teaching, the Spirit they received, and the gospel they heard and believed from the beginning (4).
Paul reminded them of the gospel they first heard and took their stand in his first letter to them in chapter 15. According to 11:22 in this letter, the “super-apostles” were Jews presenting a Jesus cast in the mold of Judaistic teaching. They focused on ceremony, keeping to Old Covenant Laws, and Jewish traditions to earn salvation. These are part of a false gospel, and they go against Jesus’ teachings.
The method of presentation is not as important as what is presented. (6) Paul was not a trained speaker, using the skills, references, and flourishes of professional rhetoric. His adversaries used a professional type of oratory as their stock in trade. Paul’s gift was knowledge, not only of Christ and Scriptures, but of human nature and the world God created.
So, as I listen and read what people who claim to be Christian present, I need to weigh it against the Bible, especially what the apostles wrote in the New Testament, for Jesus fulfilled and nullified the Old Testament. In doing so, I will not be led astray.

