When Paul and his companions left Caesarea, some other disciples joined them (which shows their courage, since they knew of the perils that lurked ahead). Mnason was among those who joined them. This man was evidently among some of the first converts to Christ and was glad to provide lodging for the group. After arriving in Jerusalem, Paul and his group received a warm welcome from the church there. Other portions of the New Testament make it clear that it was on this trip that Paul brought some relief (i.e., a financial gift) for the Christians in Judea (cf. Acts 24:17; Rom. 15:26-31). Before arriving in Jerusalem, Paul had expressed some concern about whether or not the Jewish Christians would accept the gift he brought from the Gentile Christians. The fact that he was received gladly at this time would have been a significant relief to Paul.
"On the following day Paul went in with us to James, and all the elders were present. When he had greeted them, he told in detail those things which God had done among the Gentiles through his ministry. And when they heard it, they glorified the Lord. And they said to him. 'You see, brother, how many myriads of Jews there are who have believed, and they are all zealous for the law; but they have been informed about you that you teach all the Jews who are among the Gentiles to forsake Moses, saying that they ought not to circumcise their children, nor to walk according to the customs. What then? The assembly must certainly meet, for they will hear that you have come. Therefore do what we tell you: We have four men who have taken a vow. Take them and be purified with them, and pay their expenses so that they may shave their heads, and that all may know that those things of which they were informed concerning you are nothing, but that you yourself also walk orderly and keep the law. But concerning the Gentiles who believe, we have written and decided that they should observe no such thing, except that they should keep themselves from things offered to idols, from blood, from things strangled, and from sexual immorality" (Acts 21:18-25).
Paul met with James (believed to be the author of the epistle bearing his name and also a half-brother of Jesus) as well as the elders and reported to them how the gospel was being spread and many great things were happening for the cause of Christ among the Gentiles. Everyone was thrilled to hear this wonderful news! They glorified the Lord, not Paul (and rightfully so). Luke then begins detailing one of the most difficult passages in the book of Acts.
James and these elders were Jewish Christians (i.e., Christians who had Jewish backgrounds). They informed Paul that there were many Jewish Christians gathered in Jerusalem (for Pentecost) who were very zealous for the Law of Moses. Evidently the majority of Jewish Christians continued to come to feasts and keep other regulations prescribed by Moses. However, these same souls had been told that Paul had been teaching Jews who lived among Gentiles to forsake the Law of Moses and the ancient practices of Judaism, including circumcision. Such a view was not completely accurate, for there is a big difference in affirming something is not necessary and in stating that something must not be done. Regardless, Paul's presence was certain to cause significant problems in the church because of this rumor, and James and the elders inquire as to what should be done.
Paul's presence in Jerusalem would not go unnoticed by the Christians there, so James and the elders suggest a pro-active approach to deal with the issue. They command Paul to do the following - "Take them [the four men who had taken a vow] and be purified with them, and pay their expenses so that they may shave their heads [indicating the completion of their vow], and that all may know that those things of which they were informed concerning you are nothing, but that you yourself also walk orderly and keep the law." It appears that these men had taken a Nazirite vow (cf. Num. 6). James and the elders are convinced that this suggested course will help maintain peace in the church (and would be more effective than Paul merely denying the accusations verbally). They are not arguing for the Gentiles to adopt Jewish customs, as they make clear in the next verse (Acts 21:25). That issue had already been dealt with back in Acts 15.
In our next lesson we will consider what Paul did in response to the suggestions the Jewish Christians strongly urged him to take here. His act of purification is certainly viewed in a controversial light, though I believe there is a reasonable explanation for his behavior and that it was not sinful at that time.