Romans 2:25

Circumcision indeed profiteth, if thou keepest the law; but if thou art a transgressor of the law, thy circumcision is become uncircumcision.

Acts 7:51

as your fathers, so do ye.

Romans 2:23

Thou that gloriest in the law, dost thou by transgressing the law dishonour God?

Romans 2:28-2

For he is not a Jew, who is one in outward shew, neither is that circumcision which is apparent in the flesh.

Romans 4:11-12

And he received the sign of circumcision, a seal of the righteousness of the faith, which he had in uncircumcision, that he might be the father of all who believe in uncircumcision, that righteousness may be imputed to them also,

Galatians 5:3-6

For I testify again to every man that is circumcised, he is a debtor to do the whole law.

Galatians 6:15

For in Christ Jesus neither circumcision is any thing, nor uncircumcision, but a new creation.

Ephesians 2:11-12

Wherefore remember, that ye being in time past Gentiles in the flesh (who were called the uncircumcision, by that which is called the circumcision made with hands in the flesh) Were at that time without Christ,

Treasury of Scripture Knowledge

Summary

For circumcision verily profiteth, if thou keep the law: but if thou be a breaker of the law, thy circumcision is made uncircumcision.

Bible References

But if

Romans 2:23
Thou that gloriest in the law, dost thou by transgressing the law dishonour God?
Acts 7:51
as your fathers, so do ye.