'Judaism' in the Bible

Phrygia and Pamphylia, Egypt and the districts of Libya around Cyrene, and the visitors from Rome, both Jews and proselytes (Gentile converts to Judaism),

When the congregation of the synagogue had been dismissed, many of the Jews and the devout converts to Judaism followed Paul and Barnabas, who, talking to them were urging them to continue in the grace of God.

You have heard of my career and former manner of life in Judaism, how I used to hunt down and persecute the church of God extensively and [with fanatical zeal] tried [my best] to destroy it.

And [you have heard how] I surpassed many of my contemporaries among my countrymen in [my advanced study of the laws of] Judaism, as I was extremely loyal to the traditions of my ancestors.

But when I saw that they were not being straightforward about the truth of the gospel, I told Cephas (Peter) in front of everyone, “If you, being a Jew, live [as you have been living] like a Gentile and not like a Jew, how is it that you are [now virtually] forcing the Gentiles to live like Jews [if they want to eat with you]?”

For there are many rebellious men who are empty talkers [just windbags] and deceivers; especially those of the circumcision [those Jews who insist that Gentile believers must be circumcised and keep the Law in order to be saved].