Acts 16:3-5 3Paul wanted this one to go out with him, and after taking him, he circumcised him because of the Jews who were in those places, for they all knew that his father was a Greek. 4And as they passed through the cities, they delivered to them to follow the decrees that had been decided by the apostles and elders who were in Jerusalem. 5So, the churches were strengthened in the faith, and they increased in numbers daily.
Paul may have saw all the qualities in Timothy that Luke listed in the previous verses and saw in him potential. He asked him to be a partner and young apprentice in the ministry. The surprise of verse 3 is that Paul circumcised Timothy, especially after the outcome of the Jerusalem council and the message of freedom he proclaimed to the Gentiles. One possibility is that Timothy’s mother was Jewish, making him part Jewish. Timothy could be criticized by the Jews for not embracing his heritage, which would then be a hindrance to effective ministry. Although Paul was against circumcision as a requirement to become a believer, he did not abandon Judaism or circumcision. He just put this ritual practice in its proper place in Jewish life as a sign of the covenant of faith (Romans 2:25-29).
Timothy could be a witness to both Jews and Gentiles because of his mixed ethnicity. Ethnicity and cultural background can be useful means of sharing the gospel when put in their right perspective before the cross of Christ. Paul set the pattern, as he wrote in 1 Corinthians 9:19-23 about becoming all things to all people in order to save them. If it meant being Gentile, he would do that. If it required being fully Jewish, he would do that also. The bottom line was the mission of proclaiming the good news of Jesus Christ.
Paul, Silas, and Timothy now made a small evangelistic team. They traveled throughout the area, preaching the gospel and sharing the decision of the Jerusalem church with the established churches. These cities were far away and not beholden to Jerusalem in any way. Yet, Paul and the team felt it important to keep the church unified. The word from Jerusalem also would have relieved churches struggling to reach out to their Gentile communities. The new word opened the floodgates of interest, and the church grew every day. The Gentiles experience a new freedom in Christ, but this also came at the cost of changing their lifestyles, which could require from some rejecting their immoral and idolatrous culture. They would now become a minority, but they put their new faith in Christ above all the social pressure they might experience.