CIRCUMCISION

Origin

The original circumcision instructions, given to Abraham as part of the God / Abraham Covenant are recorded in Genesis 17:1-14. These instruction became part of the Mosaic system and it later becoming part of the Passover instructions, Exodus 12:43ff.
The act of circumcision is first a spiritual sign, part of the Covenant and then secondarily as a national sign, indicating that the person was a member of the nation of Israel.

In The New Testament

Though the original Jewish church considered circumcision as very important, the requirement quickly faded from the Christian church, Rom 2:17-29, Paul here points out that circumcision was just a sign, keeping the commandments of God in the persons heart was far more important.

See also 1 Cor 7:17-19;
Gal 5:1-6;
Gal 6:15;
Col 2:2-15.

New Testament Events.

At one point there was a discussion by the Jewish members of the Christian church on circumcision, whether it was necessary as part of the church membership, they wanted to include the Mosaic instructions as part of the Christian faith. (see Acts 15:1-11). It was accepted by the then church leaders that the Gentile believers did not need to be circumcised.

A situation now arises with Titus and Timothy concerning their circumcision. Paul refusing to circumcise Titus, yet agreeing to circumcise Timothy? Why? Because there existed two very different situations. Timothy was part Jew, part Gentile and his lack of circumcision would have hindered his ministry among the people of Israel. While Titus was a full Gentile, and for him to have submitted to being circumcised would have shown to other Gentile believers that he was missing something in his Christian experience and they should also be circumcised.
James, the leader of the church, gave the following conclusion, Acts 15:13-21. As Jewish as he was, he made it clear that a Gentile does not have to become a Jew in order to become a Christian because Jews and Gentiles are saved the same way: through faith in Jesus Christ.