What did the men from Judea teach the Gentile believers in Acts 15:1?

The men from Judea taught the Gentile believers at Antioch that salvation required circumcision according to the manner of Moses. They said, “Except you be circumcised after the manner of Moses, you cannot be saved,” attempting to bring those believers back under the law of Israel.

Les explains that certain men came down from Judea to Antioch and taught the Gentile believers there that unless they were circumcised after the manner of Moses, they could not be saved. This was the same set of events Paul reports in Galatians 2. These Judaizers were still under the law and could not fathom that the God of Abraham would save pagans without bringing them under Israel’s law. The Jewish believers at Jerusalem were so saturated with the law that they tried to bring the Gentile believers of Paul’s ministry at Antioch under it.

Acts 15:1

And certain men which came down from Judaea taught the brethren, and said, Except ye be circumcised after the manner of Moses, ye cannot be saved.

Who does Les associate with the Judaizers in the Acts 15 controversy?

He associates Peter, James, and John with the Judaizers in the Acts 15 controversy, placing them alongside many Judaizers. He also identifies the emissaries of the Twelve and certain believing Pharisees who demanded circumcision and Mosaic law observance as connected to that same controversy.