Notice the focus on the matter of Gentiles and the effectiveness of the Gospel’s message. This, of course, makes perfect sense, as Paul is primarily known as the Apostle to the Gentiles. At the same time however, he addresses himself to Jews as well, as his congregations (household meal gatherings in honor of Jesus) are a mixed bag, consisting of both Jews and Gentiles. This is well demonstrated not only by the content of his letters, but by the fact that he spends a great deal of time addressing Jews in the synagogues in the various Gentile-dominated cities to which he travels.
However, Luke, as the author of Acts, is free to pick and choose that upon which he focuses his attention and that which he relays to the readers/hearers of his work. Interestingly, he consistently chooses to impart information concerning Gentiles, with this information provided its contextual setting by the Jew/Gentile issue that consumed the energy of the nascent church and so much of Paul’s attention. This lends substantial weight to the idea that the means by which Gentiles are included in the covenant people and share in their promises (the means by which they are justified) was a (if not the) fundamental point of contention in the early church.
Verse twenty provides the response: “When they heard this, they praised God. Then they said to him, ‘You see, brother, how many thousands of Jews there are who have believed, and they are all ardent observers of the law” (Acts 21:20). That is, they are believers in Jesus who continue to adhere to the covenant markers of circumcision, Sabbath-keeping, and dietary laws. Going on, “They have been informed about you---that you teach all the Jews now living among the Gentiles to abandon Moses, telling them not to circumcise their children or live according to our customs” (21:21). This, as can be gleaned from Paul’s letters, is highly debatable, and probably something of a distortion or half-truth (at best).
Paul’s primary concern was the covenant marker of Gentiles, that being confession of Jesus as Lord (their confession of the Gospel) that made them people of the covenant, and not the submission to the ongoing covenant markers of Israel as that which made them people of the covenant. Paul was not concerned with whether or not the Jews continued to hold to these customs, being far more concerned with not forcing Gentiles to submit to them, as doing so would contribute, in his mind, to erecting barriers to the spread of the kingdom of the Creator God to all peoples. Paul clearly demonstrates his belief that it would create unnecessary and probably unhelpful divisions among people, with these divisions based solely on identifying practices that had nothing to do with the proclamation of the Lordship of Jesus.
If anything, Paul’s preaching probably encouraged Judaizing Gentiles (Gentiles who had adopted the covenant markers of Israel so as to come under the auspices and provisions of the covenant, so becoming Jews) to discontinue Sabbath-keeping and adherence to dietary laws (reversing circumcision, though possible, would probably not be encouraged, especially considering that Jews were not the only people to practice circumcision---it was really the combination of covenant related activities, though these changed over the years to reach the form that they had taken by the time of Jesus and Paul, that served to set Israel apart from other peoples). This could form the basis for the mild accusation heard in the twenty-first verse, as, in order to make a point, they would not make an effort to distinguish between a Jew of national and ethnic Israel, and someone who had become a Jew through the required processes. Though this study will not dwell on it, this chapter and its recorded exchange provides an indication that there may have been something of a struggle for honor within the church, with what has already come and what follows serving as an attempt to shame Paul.