Romans 2:25

For circumcision indeed is advantageous, if thou practise the law: but if thou art a transgressor of the law, thy circumcision becomes uncircumcision,

Acts 7:51

Ye stiff-necked and uncircumcised in heart and in ears, ye do always oppose yourselves against the Holy Ghost: as your fathers, so are ye.

Romans 2:23

thou who gloriest in the law, dishonourest thou God by the transgression of the law?

Romans 2:28-2

For not he who is outwardly such, is the Jew; neither is that which is outward in the flesh, circumcision.

Romans 4:11-12

And he received the sign of circumcision, as a seal of the righteousness of the faith which he had when uncircumcised: that he might be the father of all those who believe, though uncircumcised; that to them also the righteousness might be imputed:

Galatians 5:3-6

And again, I testify to every man who is circumcised, that he is under an obligation to keep the whole law.

Galatians 6:15

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

Ephesians 2:11-12

Wherefore remember that ye in time past were Gentiles in the flesh, who are called uncircumcision by that called circumcision made by hands in the flesh;

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 who gloriest in the law, dishonourest thou God by the transgression of the law?
Acts 7:51
Ye stiff-necked and uncircumcised in heart and in ears, ye do always oppose yourselves against the Holy Ghost: as your fathers, so are ye.