In Romans 2:25-29, Paul points out the contradiction between the claim of the Jews that they are righteous in view of their conduct by highlighting the matter of circumcision. He writes:
25 For circumcision is indeed profitable if you keep the law; but if you are a breaker of the law, your circumcision has become uncircumcision.
26 Therefore, if an uncircumcised man keeps the righteous requirements of the law, will not his uncircumcision be counted as circumcision?
27 And will not the physically uncircumcised, if he fulfills the law, judge you who, even with your written code and circumcision, are a transgressor of the law?
28 For he is not a Jew who is one outwardly, nor is circumcision that which is outward in the flesh;
29 but he is a Jew who is one inwardly; and circumcision is that of the heart, in the Spirit, not in the letter; whose praise is not from men but from God. (NKJV)
Circumcision was given as a command to Abraham and his descendants as an outward sign of a spiritual reality. Without a circumcision of the heart, the symbol carried no meaning.
I wear a wedding band. If I pointed to that and said, “This is a marriage” that would be a stupid statement. It isn’t marriage, but it is a symbol of it. Putting one on doesn’t make me married and wearing one as a symbol of fidelity is meaningless unless accompanied by faithfulness to the marriage vows. The Jews looked at circumcision that way. They thought the ritual was righteousness. Furthermore, so long as they were circumcised, they believed they were going to heaven whether they were committed to God or not. Many of the rabbis taught this.
What circumcision meant under the Old Covenant, baptism means under the New Covenant. It is a symbol of our relationship with Christ though it isn’t the same as a relationship with Christ. Baptism is important. It is a way to publicly profess one’s faith. Yet, water has no power to cleanse us from sin, if we haven’t been cleansed already by the blood of Christ. Then and only then does the symbol have meaning.
There are many who tragically enter the baptismal pool as dry sinners and come out on the other side as wet sinners! They advertise they are dead to sin and alive in Christ through the rite of immersion and yet are still dead in trespasses and sins. Don’t be in that number!