The Jews feared that if the restrictions and ceremonies of their law were not made obligatory upon the Gentiles as a condition of church fellowship, the national peculiarities of the Jews, which had hitherto kept them distinct from all other people, would finally disappear from among those who received the gospel message.
The Jews had always prided themselves upon their divinely appointed services, and many of those who had been converted to the faith of Christ still felt that since God had once clearly outlined the Hebrew manner of worship, it was improbable that He would ever authorize a change in any of its specifications. They insisted that the Jewish laws and ceremonies should be incorporated into the rites of the Christian religion. They were slow to discern that all the sacrificial offerings had but prefigured the death of the Son of God, in which type met antitype, and after which the rites and ceremonies of the Mosaic dispensation were no longer binding.
Before his conversion Paul had regarded himself as blameless "touching the righteousness which is in the law." Philippians 3:6. But since his change of heart he had gained a clear conception of the mission of the Saviour as the Redeemer of the entire race, Gentile as well as Jew, and had learned the difference between a living faith and a dead formalism. In the light of the gospel the ancient rites and ceremonies committed to Israel had gained a new and deeper significance. That which they shadowed forth had come to pass, and those who were living under the gospel dispensation had been freed from their observance. God's unchangeable law of Ten Commandments, however, Paul still kept in spirit as well as in letter.¹

Reference(s):

¹ The Acts of the Apostles, pp. 189, 190.