A NPP view on Gal 3:10
Somewhere a while ago I came across the idea (I forget where) that, in Galatians, part of Paul's criticisms are aimed at the Galatians only following some of the customs of the law but not others. These view struck me at the time as having great merit, and as time has passed I've only become more convinced it is correct. Here I'm going to comment on this view as it pertains to the interpretation of Gal 3:10, in which Paul writes:
For all who rely on the works of the law are under a curse; for it is written, "Cursed is everyone who does not observe and obey all the things written in the book of the law."
Firstly, Jews in general weren't of the view that they were failing to obey the law. They thought they were succeeding. They didn't think they came under this curse for failing to observe the entire law, because they did observe it in general. They didn't do it perfectly, but they didn't think perfection was required. Secondly, given Sanders' presentation of Judaism it would make most sense if this curse was understood not as a demand for perfection in following the law but as a command to not neglect parts of the law entirely. ie the point is quantitative not qualitative - "follow all the laws and not just some of them" rather than "follow perfectly those you do follow". In other words, it would seem to be most faithful to the typical Jewish understanding of this curse if Paul's view was "Cursed is everyone who picks and chooses which parts of the law they obey" rather than "Cursed is everyone because no one achieves perfection".
Furthermore, given the way that curses were understood to work in the ancient world, it seems likely that Paul would have understood this curse to work as follows. People who were not part of the covenant were completely free of the curse. People who were part of the covenant came under its (complex) array of blessings and curses, which effectively hung over them in readiness to apply should their conditions of activation be met. In this sense all who followed the law were at all times "under" inactive blessings and curses which would trigger conditionally on behavior. Thus this curse would become active if someone started obeying part of the law (and thus made this curse relevant to them) but not all parts of it (and thus triggered the conditions of the curse).
Of course, whether Paul really believed in the metaphysical reality of curses might be questionable (though the province of Galatia was famous within the Roman empire for their belief in the reality of curses, which explains why curse language occurs in Galatians far more than Paul's other epistles), but it makes little exegetical difference if Paul simply read God's curse as written in the Law as meaning "I, God, do not approve of X" rather than as a real magical curse.
All this seems to demand we read Paul's statement as meaning that if the Galatians Christians start observing some of the rituals of the law then this is bad. God does not approve of only following some of the rituals - hence the curse - a person has to either obey all the laws or none of the laws, picking and choosing is not an option. Is this what Paul is saying in Galatians? Yes. That's what it looks like to me. In Gal 5:3 he says:
Once again I testify to every man who lets himself be circumcised that he is obliged to obey the entire law.
It seems to me then that the Galatian Christians have started obeying some of the laws but not all of laws in a belief that this is what God wants of them. Paul is upset by this on two fronts. One, that their practice of simply following some Jewish customs has no merit to it in and of itself. Two, that their belief that they need to follow the law at all is faulty. We see these precise two points stated in this order by Paul in Gal 3:10-12 (as well as elsewhere in the letter).