Romans 2:25 // Circumcision

Based on Romans 2:25

25 For circumcision verily profiteth, if thou keep the law: but if thou be a breaker of the law, thy circumcision is made uncircumcision. 26 Therefore if the uncircumcision keep the righteousness of the law, shall not his uncircumcision be counted for circumcision? 27 And shall not uncircumcision which is by nature, if it fulfil the law, judge thee, who by the letter and circumcision dost transgress the law? 28 For he is not a Jew, which is one outwardly; neither is that circumcision, which is outward in the flesh: 29 But he is a Jew, which is one inwardly; and circumcision is that of the heart, in the spirit, and not in the letter; whose praise is not of men, but of God.

The early apostolic church was predominantly Jewish. The coming of Jesus changed the ceremonies of the Jewish religion to new ceremonies like the Lord's Supper, Foot Washing, Baptism and Ordination of Pastors. But many vocal Jews - even the apostles - were reluctant to stop practicing the Jewish feast days, sacrifices and ceremonial laws. Because of his vision of the unclean animals Peter learned to stop observing the Pharisaic laws and customs (Acts 10-11) that Jesus had ignored during his ministry, which especially made it hard to preach to Gentiles. But Paul was the first person I know of that was humble enough for God to show that even Moses' Ceremonial Law was not binding.
Circumcision was a particularly big issue; allowing uncircumcised Christians would open the door for many Gentiles and dilute the Jewishness of Christianity. From the Roman perspective, Christianity would become a new cult rather than a sect of Judaism, and being a peaceful religion potentially weaken the military strength of the empire. Abandoning circumcision allowed many Gentile men to enter the church; but turned Jews and Romans against the Nazarene Sect generating persecution, which Paul himself was an early victim of. As the crucial distinction that defines Christianity as a separate religion from Judaism, circumcision is very important, and dealt with thoroughly in the Greek Scriptures. Paul defends the position that circumcision was never a requirement for salvation and that Jews that make it a requirement for salvation (Acts 15) are leaving the original faith and should be disfellowshipped/separated from (Gal 5:12).
Paul approaches the issue cautiously. In the Bible, circumcision is a good thing that the Jews were to do as a part of keeping the law, but if they did not keep the law it did not matter if they were circumcised, they were still sinners. Uncircumcision among Jews represented sin and circumcision salvation, but even if you were circumcised once, if you sinned you would lose your salvation. Judas, Annas and Caiaphas are good examples of circumcised people that were sinners, but you can find examples through the Hebrew Scriptures too. It is clear that just being circumcised, just having been saved at one point, doesn't guarantee salvation in the end. So if circumcision can be useless because of sin, uncircumcision can be unimportant because of keeping the moral law of the Ten Commandments. Breaking God's moral law in order to keep customs and traditions is wrong. Those who are true Jews, God's people at this time are those that care about pleasing God more than pleasing other people by keeping their customs and traditions. They are those that trust Jesus and follow his commandments.
Not only conservative people have customs and traditions; "political correctness" is a kind of tradition and fashion is a kind of custom. Any way of doing things that can be learned is a custom or tradition, and they are not bad if they are in line with the deep meaning of the Ten Commandments. But anything people "do" that is against God's plan is not excusable. This includes what you read, watch, study; where you study, what kind of job you look for, what clothes and accessories you wear, what you eat; it includes all aspects of your life. Follow God's plan in all areas of your life, don't just do what everyone around you does.
Being circumcised or not is not the point, obedience to God, especially in being fair and kind to those around you is what you need. To get this, think about Jesus and what he has done for you, by thinking about him you will become more like him.