The church was originally a Jewish church. They followed Jewish customs, worshipped in the Jewish Temple, were highly regarded in Jewish society (Acts 5:13) and continually grew in number including gaining a number of followers from the Jewish priests (Acts 6:7). The persecution of Christians in Jerusalem had ceased since the time of Paul’s conversion which meant the church was meeting openly and many who followed the Law rigidly, such as the Pharisees, had joined the believers. These rigid Law abiding Jews lived and preached Jewish legalism among the ranks of the early Jerusalem church and were known as the circumcised believers. Obviously Peter and the rest of the Jewish apostles were also circumcised, but circumcision and obedience to the Jewish law was not the doctrine Jesus had sent the apostles into the world to preach. They had been told to teach Christ’s doctrine to the Gentiles, not the Mosaic Law to the Gentiles:
“Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you.” – Matthew 28:19-20
Peter seriously violated the circumcised believers’ standards of Jewish holiness when he enter the house of Cornelius, an uncircumcised Gentile, and, then, actually ate a meal with the Gentile centurion in his home.
Clearly, the early church in Jerusalem is struggling to understand the Gospel without Jewish colored glasses. The apostles themselves had to make many cultural adjustments when they traveled with Jesus who introduced the new phase of the kingdom of God called the Church. Many Jews, including Jesus brother James who became the leader of the Jerusalem church, continued to follow Jewish customs and worship on the Temple Mount. Why not? They were Jews and this was their culture. Yet, when they went to teach the Gentiles men like Peter, Paul and John did not teach Jewish culture or demand obedience to the Law of Moses. These men preached the message of Jesus. Yet, a group of Jews, called the Circumcision Group would not accept this distinction. They continued to teach circumcision and legalistic obedience to the Law of Moses to the Gentile churches. These circumcised believers would continue to be a problem for Paul in most of his churches in Gentile cities.
“Watch out for those dogs, those men who do evil, those mutilators of the flesh. For it is we who are the circumcision, we who worship by the Spirit of God, who glory in Christ Jesus, and who put no confidence in the flesh.” – Philippians 3:2-3
“Neither circumcision nor uncircumcision means anything; what counts is a new creation.” – Galatians 6:15
“He (Peter) began to draw back and separate himself from the Gentiles because he was afraid of those who belonged to the circumcision group.” – Galatians 2:12