From Reza Aslan’s book Zealot:

Paul’s second trip to Jerusalem took place about a decade later, sometime around 50 C.E., and was far less cordial than the first. He had been summoned to appear before a meeting of the Apostolic Council to defend his self-designated role as missionary to the gentiles (Paul insists he was not summoned to Jerusalem but went of his own accord because Jesus told him to). With his companion Barnabas and an uncircumcised Greek convert named Titus by his side, Paul stood before James, Peter, John, and the elders of the Jerusalem assembly to strongly defend the message he had been proclaiming to the gentiles.

… According to Luke, James, in his capacity as leader of the Jerusalem assembly and head of the Apostolic Council, blessed Paul’s teachings, decreeing that thenceforth gentiles would be welcomed into the community without having to follow the Law of Moses, so long as they “abstain from things polluted by idols, from prostitution, from [eating] things that have been strangled, and from blood” (Acts 15: 1– 21). Luke’s description of the meeting is an obvious ploy to legitimate Paul’s ministry by stamping it with the approval of none other than “the brother of the Lord.” However, Paul’s own account of the Apostolic Council, written in a letter to the Galatians not long after it had taken place, paints a completely different picture of what happened in Jerusalem. Paul claims that he was ambushed at the Apostolic Council by a group of “false believers” (those still accepting the primacy of the Temple and Torah) who had been secretly spying on him and his ministry. Although Paul reveals little detail about the meeting, he cannot mask his rage at the treatment he says he received at the hands of “the supposedly acknowledged leaders” of the church: James, Peter, and John. Paul says he “refused to submit to them, not even for a minute,” as neither they, nor their opinion of his ministry, made any difference to him whatsoever (Galatians 2: 1– 10). Whatever took place during the Apostolic Council, it appears that the meeting concluded with a promise by James, the leader of the Jerusalem assembly, not to compel Paul’s gentile followers to be circumcised. Yet what happened soon afterward indicates that he and James were far from reconciled: almost immediately after Paul left Jerusalem, James began sending his own missionaries to Paul’s congregations in Galatia, Corinth, Philippi, and most other places where Paul had built a following, in order to correct Paul’s unorthodox teachings about Jesus…

Nevertheless, James’s delegations seem to have had an impact, for Paul repeatedly lambastes his congregations for abandoning him: “I am amazed at how quickly you have deserted the one who called you” (Galatians 1: 6). He implores his followers not to listen to these delegations, or to anyone else for that matter, but only to him: “If anyone else preaches a gospel contrary to the gospel you received [from me], let him be damned” (Galatians 1: 9). Even if that gospel comes “from an angel in heaven ,” Paul writes, his congregations should ignore it (Galatians 1: 8). Instead, they should obey Paul and only Paul: “Be imitators of me, as I am of Christ” (1 Corinthians 11: 1)…

Regardless, by the year 57 C.E., the rumors about Paul’s teachings could no longer be ignored. And so, once again, he is summoned to Jerusalem to answer for himself. This time, James confronts Paul directly, telling him that it has come to his attention that Paul has been teaching believers “to forsake Moses” and “not circumcise their children or observe the customs [of the law]” (Acts 21: 21)…

To clear up matters once and for all, James forces Paul to take part with four other men in a strict purification ritual in the Temple— the same Temple that Paul believes has been replaced by the blood of Jesus— so that “all will know there is nothing to the rumors said about you, and that you observe and guard the law” (Acts 21: 24). Paul obeys; he seems to have no choice in the matter.