What is a Judaizer in the Bible?
A Judaizer was a believer that Jesus was the Christ, saved under the kingdom gospel, yet did not comprehend the grace of God or that the law had been satisfied and set aside. Judaizers followed Paul, insisting his converts must also practice Judaism, be circumcised, and keep the law.
Les explains that a Judaizer was a believer that Jesus was the Christ and was saved under that kingdom gospel, but they still did not comprehend the grace of God and that the law had now been satisfied and totally set aside. So the Judaizers constantly followed in Paul's footsteps, telling his converts, "Now wait a minute, you can't be saved on just Paul's gospel alone. You still have to practice Judaism. You have to be circumcised, you have to keep the law, and so on." This just about drove the apostle up the wall, and Paul suffered because of that. It connects with his defense of his apostleship in the early chapters.