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.
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 since nobody does perfectly 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).
Righteousness of the law (v.26) — an effort to obey one’s conscience
Inwardly (v.29) = 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).
In the spirit, not in the letter (v.29) — The NKJV capitalizes “Spirit,” making it a reference to the Holy Spirit. But Old Testament believers weren’t indwelled with the Spirit—He only came upon certain people for certain lengths of time to perform certain tasks. I think it’s possible that “spirit,” here, refers to the motivation of the person obeying the law—whether they do it by faith, or as a checklist. Although that still leaves a question about what Jesus was talking about to Nicodemus in John 3:3-6 (My notes on that passage are not particularly helpful) :
3 Jesus answered and said to him, “Most assuredly, I say to you,unless one is bornagain, he cannot see the kingdom of God.”
4 Nicodemus said to Him, “How can a man be born when he is old? Can he enter a second time into his mother’s womb and be born?”
5 Jesus answered, “Most assuredly, I say to you,unless one is born of water and the Spirit, he cannot enter the kingdom of God.
6 That which is born of the flesh isflesh, and that which is born of the Spirit is spirit.