Did the Jewish believers who troubled the Gentile churches believe Paul's gospel?
No. The Jewish believers troubling the Gentile churches were not believers of Paul's gospel. They believed Jesus was the Christ, the Messiah of Israel, and remained under the Law. Having come under Peter's preaching, they were still Law-keeping Jews, not followers of Paul's gospel message.
Les explains that the Jews coming into Gentile congregations and troubling them were not the Orthodox or Pharisees, who would have nothing to do with such settings and viewed Gentiles as dirty dogs. Instead, they were Jewish believers that Jesus was the Christ. But they were not believers of Paul's Gospel; they still believed Jesus was who He said He was, the Messiah of Israel, and so they remained under the Law. Those early Jewish believers under Peter's preaching were still Law-keeping Jews, which clarifies the conflict addressed in Acts 15.
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.
Why were the Jewish believers in Jerusalem upset with Paul and Barnabas?
The Jewish believers in Jerusalem were upset because Paul and Barnabas were bringing Gentiles into the church at Antioch and offering them God's salvation. This inclusion of Gentiles was anathema to the Jews of that time, causing consternation, so they sent men to investigate and summoned Paul and Barnabas to Jerusalem.
Were the early Jewish believers under Peter's preaching still keeping the Law?
Yes. The early Jewish believers who came under Peter's preaching remained Law-keeping Jews. They believed Jesus was the Christ, the Messiah of Israel, but they were not yet believers of Paul's Gospel. They continued under the Law, and this distinction explains the conflict in Acts 15.
More Questions
Who were the Jews that came into Gentile congregations teaching circumcision and the Law?
Those coming into the Gentile congregations were Jewish believers that Jesus was the Christ, not believers of Paul's Gospel, but still believing Jesus was the Messiah of Israel.