Gal 2:3

2:3 forced to be circumcised. See 5:12 and Acts 15:1. Circumcision was the distinguishing mark of the Jew, and the final step in the conversion of a male Gentile to the Jewish religion. Some Jewish Christians believed that Gentiles also had to accept circumcision and thus become Jews before they could be Christians and belong to God’s chosen people. Paul was vehemently opposed to this teaching and maintains throughout Galatians that we are justified by faith in Christ alone.