Paul now argues that law keeping and law breaking are central to your status as Jews (circumcised) or Gentiles (uncircumcised). He states that circumcision is of value for those who observe the Law. However, Circumcision without law-keeping is useless, you are considered uncircumcised (v25). In the same way, those who are uncircumcised but keep the law, according to Paul are reckoned or credited as circumcised. Note the use of the word λογίζομαι here which will show up again in chapter 4 to describe how faith is reckoned or credited as righteousness (v26).[1]
If this is the case, then the whenever someone does obey the law, even though they are uncircumcised, this acts as condemnation to the Jew, to the circumcised because it highlights both that the law can be kept and that they are not doing so (v27). Further it points to the fac that it isn’t the external appearance but the heart that matters. True circumcision is of the heart, not merely an outward operation. It is the work of the Holy Spirit and therefore is not merely concerned with the letter of the Law. This also means that a Jew should seek God’s approval not man’s because God looks on the heart (v29).
[1] In other words, being righteous and being circumcised are equated together. Righteousness describes the moral status of the covenant member whilst circumcision symbolises their covenant membership. There are things that can be reckoned to you or credited to your account in order to give you that status. The sense though is that it is taken as a whole. It’s not that you build up credit for each good work, rather, it is that you have the full status of a law keeper and that is what is credited to your account giving you full covenant membership.