"Central indeed, for the so-called Apostolic Council of Acts 15 has been rightly described as the centre of the book. The Council, with its Decree, can in fact be taken as Luke’s final statement of the relation of emerging Christianity to Judaism. He recognizes the alternative to the Council’s decision: all Gentile converts must be circumcised and required to observe the Torah in its entirety (15.1, 5). Acceptance of this position would have made Christianity a sect within Judaism, probably with no more future than the Qumran sectaries enjoyed. But this, Luke and his contemporaries knew, would not do. There was a new religious drive, and uncircumcised Gentiles shared it with born Jews. If God had made no distinction between them and us, cleansing their hearts by faith (15.9) and manifestly giving them the Holy Spirit (10:47), it was impossible to exclude them by demanding that they should accept the intolerable burden (15.10) of circumcision and the Law. Moreover, God had shown his approval of the mission to Gentiles by permitting, or causing, miracles (15.12). But the keystone of the argument is James's demonstration from Scripture itself that it was always God’s intention to crown the renewal of Davidic kingship by incorporating the rest of mankind in one people with the Jews (15.15–21). And all that God required (in addition to faith, adequately dealt with in 15.9, 11) was the pure religion and ethics of Judaism, with just enough of its cultus to demonstrate continuity (15.29)."
C. K. Barrett, “Luke—Acts,” in Early Christian Thought in Its Jewish Context, ed. John Barclay and John Sweet (Cambridge: Cambridge University Press, 1996), 94.