It has been common, especially among some varieties of Protestantism, to take Paul’s statements about circumcision as pieces of a theology of ritual. Paul’s statement about inward and heart circumcision in Romans 2 is transferred to rites of entry in general, especially to baptism: “Baptism is that which is of the heart, by the Spirit, not by the letter.”
It’s fairly obvious, though, that this cannot be done without qualification. Paul says, “neither is circumcision anything, nor uncircumcision,” and he would not have said the same about baptism. “There is neither Jew nor Greek,” he writes earlier in Galatians, but this is preceded by “all of you who were baptized into Christ have clothed yourselves in Christ” and he immediately adds that the reason why this distinction has been erased is because “you are all one in Christ Jesus.” Circumcision divided humanity; baptism unites it.
Paul’s statements on circumcision obviously contribute to a theology of ritual. But they are in the first instance part of a theology of covenants, statements about what the scholastics called the “sacraments of the old law,” and only as such should be used to develop a theology of ritual in general.”