What did the believing Jews at Antioch say was necessary for a Gentile to be saved?
The believing Jews at Antioch insisted that Gentiles could not be saved unless they were circumcised according to the manner of Moses and kept the Mosaic Law. They tied salvation to circumcision and legalism, arguing the Gentiles had to submit to that requirement.
Les explains that this occurred in Acts 15, around A.D. 51, about 23 years after Pentecost. The believing Jews at Antioch were still pressing the Gentiles, saying they could not be saved unless they kept the Mosaic Law and were circumcised. Paul and Barnabas had no small dissension, an argument, and insisted that circumcision and legalism could not be put on Gentile believers. Since the question could not be settled, they were sent up to Jerusalem to the twelve and the elders of the believing element, the church at Jerusalem. Along the way they declared the conversion of the Gentiles.