Having rejoiced over Paul"s account of the Gentiles" conversion, the elders also added that thousands of Jews had become believers, many of them in Jerusalem. Estimates of the population of Jersalem at this time range between30 ,000,50 ,000. [1] The elders explained that these Jewish Christians had some misgivings about Paul"s ministry about which they had heard. The word on the streets was that Paul was going beyond his actual practice of not requiring Gentile converts to undergo circumcision or to obey the Mosaic Law. They had heard he was telling Jewish converts not to practice circumcision or to observe the customs of Judaism. This was a false report. Paul did not teach that these customs were evil, just unnecessary for justification and sanctification. [source][source][source]
"The Jerusalem elders were in somewhat of a bind. On the one hand, they had supported Paul"s witness to the Gentiles at the Jerusalem Conference. Now they found Paul a persona non grata and his mission discredited not only among the Jewish populace, which they were seeking to reach, but also among their more recent converts. They did not want to reject Paul. Indeed, they praised God for his successes. Still they had their own mission to the Jews to consider, and for that Paul was a distinct liability." [2][source]
From here to the end of Acts Paul argued before various audiences that he was a loyal Jew and that his mission to the Gentiles was not anti-Jewish. He insisted that he did not oppose the Jews or their keeping of the Mosaic Law. [source][source][source]