Galatians 5:2

If ye be circumcised, Christ shall profit you nothing. If you trust to circumcision as necessary to salvation, Christ and His religion will be of no avail to you; but you seem to be putting your trust in this under the tuition of the Judaisers, although you were Gentiles, and baptized as such. Why do you tack on circumcision to baptism now? There can be no other reason for this proceeding except your belief that baptism by itself is insufficient, and needs to be supplemented by circumcision. Certainly you have not the Jews' pretext that they use circumcision in deference to their law. This may be good excuse for them; it is none for you.