What is the equivalent of circumcision legalism for Christians today?
For Christians today, the equivalent is any legalistic demand or extra requirement that people say must be added to believing the Gospel. Circumcision itself is no longer the criteria; instead, various works, rules, or conditions become modern substitutes, undermining salvation by grace through faith plus nothing else.
Les explains that Galatians shows we are not under the system of law or under any kind of legalistic demands for salvation. Salvation is all of grace by faith plus nothing else, and adding anything to it takes away from the finished work of the cross, as though Christ did not really finish it. At that time, the legalism was prompted by the Jews and was circumcision. But for us today, circumcision is not so much the criteria; rather, it is all the other things people try to tell us we have to do besides believing the Gospel.