Romans 2:25-29 — For circumcision verily profiteth, if thou keep the law: but if thou be a breaker of the law, thy circumcision is made uncircumcision.
Therefore if the uncircumcision keep the righteousness of the law, shall not his uncircumcision be counted for circumcision?
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?
For he is not a Jew, which is one outwardly; neither is that circumcision, which is outward in the flesh:
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.
Circumcision was the seal of God’s covenant.
Circumcision didn’t justify, but it did profit if a person kept the law (in the sense of endeavoring to keep it, not perfection). But nobody does keep the law, so circumcision doesn’t help save.
To be a Jew, one had to be 1) born of Abraham through Isaac and 2) spiritually in good standing with God (circumcision of the heart). So born of Abraham and born again of the Spirit.
Righteousness of the law (verse 26) — an effort to obey one’s conscience
Inwardly = literally “in secret” — not obeying the Law for show
Don’t be circumcised (in an attempt to obey the Law) unless you plan to follow the entire Law. For I testify again to every man that is circumcised, that he is a debtor to do the whole law (Galatians 5:3).
But instead … We are the circumcision, which worship God in the spirit, and rejoice in Christ Jesus, and have no confidence in the flesh (Philippians 3:3).