The Judaizers were Jewish Christians in the first-century church who insisted that Gentile converts must become Jewish in order to become Christian — specifically that they must be circumcised and keep the Mosaic ceremonial law. Paul considered this teaching so destructive that he wrote the entire letter of Galatians against it and pronounced anathema on anyone who preached it: "But even if we, or an angel from heaven, preach any other gospel to you than what we have preached to you, let him be accursed" (Galatians 1:8). The Judaizer error was not denying that Jesus was Messiah, but adding law-keeping to faith as a condition of salvation. This, Paul said, was a different gospel — no gospel at all — because it made Christ's work insufficient. The Jerusalem Council (Acts 15) formally ruled against the Judaizers and affirmed that Gentiles are saved by grace through faith without the ceremonial law. Every generation of the church has its Judaizers — teachers who add requirements to faith: keep these rules, vote this way, observe these days, dress this way, or you cannot be truly saved. Paul's letter stands as a permanent warning: anyone who adds to the gospel subtracts from it.